Final Fantasy 10 cheats: Battles

Defeating Anima:
Summon Yuna's new Aeon ???? (Shiva) and attack normally. Heal with her Ice spells on herself. When her Overdrive is full, it should kill Anima. Alternately, use Yuna's Overdrive Grand Summon on Shiva, then just attack a few times.
tsyvbaoand SailorGMoon.

When fighting Anima, carry a lot of Phoenix Downs to counter the Pain attack. Also, have Rikku steal Grenades from Anima. They are effective against him.
Sonix Wind.

Defeating Al Bhed gunner:
Have Tidus, Auron, and Kimarhi up front. Have Tidus use Cheer ten times or more. Have Auron attack, and Kimarhi heal with Hi-Potions.
Rocky22473.

To defeat the Al Bhed gunner, you must have had Rikku steal from the electric fiends in Macalania Woods. They hold Electro Marbles. Get six or more of them. Then when you are battling the Al Bhed gunner, have Rikku, Auron, and Lulu on your team. Have Lulu use Water and Ice magic attacks on it. Have Auron use regular attacks on it. Have Rikku use the Electro Marbles. The Electro Marbles take up to 300 to 600 damage. It is very effective if you use a lot of them.
Kasai.

Defeating Behemoth Kings:
If you have a weapon with "Stonestrike" or "Stone Touch" equipped and manage to use it in the finishing hit, the Behemoth King will not do his "Meteor" counter-attack before dying.
RedLantern62288.

Defeating Biran:
When fighting Biran and Yenke with Kimahri, use Lancet on each of them a few times. You should get a few Ronso Rages. Use Lancet again after Biran has used Mighty Guard to also obtain it.
Daniel Cooper.

First, do not discover almost (since you have to learn some attacks to survive) any Ronso Rage attacks, but make sure to level up very well. You should also know Black Magic, White Magic, Use, And Steal/Mug (recommended). You should at least be equipped with the Red Armlet (From the Killika Cloister of Trials) and any weapon with status ailments. Yenke and Biran's HP should be about Kimahri's HP. When the battle starts, use Lancet on Biran to learn a new attack and your Overdrive gauge will be filled. Now, stop. Use the Overdrive you just learned (except Stone Breath as it will not do any damage , or Self-Destruct) and attack. Keep repeating this, and when you can learn no more attacks from Biran, use Lancet on Yenke then use the attacks on him. When someone uses White Wind and/or Mighty Guard, use Lancet on them and you will learn them. Finally, use Mighty Guard to protect yourself and keep attacking. Both Ronsos and the Ronso Duo will be defeated.
DiamondDice8245.

Defeating Bomb:
Bombs become stronger in the Al Bhed Home and on the Al Bhed airship. This trick will take about five minutes to complete. First, have Wakka, Auron, and Kimarhri out on the field at the same time. Make sure Wakka's MP is above 45. Also, make sure that Wakka knows Dark Attack, Silence Attack, and Sleep Attack. Let Kimarhri's weapon be the Snakehead. Make sure Auron knows Power Break and Magic Break. Start by having Auron use Power Break and Magic Break on all three. Next, have Wakka use Dark Attack, Silence Attack, and Sleep Attack on them. Then, use Kimarhri's weapon the Snakehead on them. The Snaakehead poisons the enemy. Finally, have Wakka use Sleep Attack on them. The rest of the fight you can put them on the defensive position.
fabu5.

Defeating Braska's final Aeon:
Use Yuna to summon all her Aeons. Use their Overdrives to defeat its first form. To defeat its second form, use Magus Sisters and keep doing their specials. When it is Overdrive time for Magus Sisters, use it. This battle is not to difficult. Also use Kimahri's Zombie Break attack on it to inflict Zombie on it.
Mooncodan.

Summon three Aeons first for the first form. For the second form, summon two Aeons. Then just use Zombie attack on him and use Curaga with yuna. Next, use Quick Hit with Tidus. Use the strongest person to remain alive and Phoenix Down Tidus or Yuna. Note: You must have your strongest weapons equipped.
Armygal619.

Make sure everyone in your party (except for Kimahri) is equipped with their legendary weapon at full power. Have Auron start the fight with his Overdrive Banishing Blade. This will increase the amount of damage you can do to him. Then, have Tidus cast Hastega. If one of your characters should get Petrified, immediately use a Soft. Have Yuna doublecast Ulima. That should do about 12,000 damage per casting. Then, have Tidus use Quick Hit. It should do about 13,500 damage to the Aeon. Next, have Yuna doublecast Ultima again and the Aeon should transform. If it does not, keep attacking it until it does. After it transforms, switch Auron for Rikku and use her overdrive Mix and combine two Gambler's Spirits. On Tidus' next turn, have him use Blit Ace. Then, have Yuna summon the Magus Sisters and unleash their Overdrive. Then, dismiss them. On Yuna's next turn, have her Grand Summon the Magus Sisters and use their Overdrive again. Finally, have Rikku attack the Aeon to finish it off.
Coro175.

First, go to Omega Ruins, defeat Ultima Weapon, but steal 10 to 20 Doors To Tomorrow first. On the Aeon's first form, get Rikku's Overdrive, make her mix two Doors To Tomorrow (Trio of 9999) and have Tidus and Auron with her in battle at the time. Keep Auron, Rikku and Tidus alive throughout the entire battle. On the second form, have Lulu Doublecast Ultima to start of the battle, then bring back Tidus, Auron and Rikku. While they do 9999 damage, they will also heal for 9999 (have 99 Al Bhed or Mega-Potions on hand).
Jose Alvarez.

Use Yojimbo's Overdrive to instantly kill the Boss.
Stian Ingwall.

Train the Magus Sisters and Anima until they are in Overdrive. Use Anima's overdrive for the first form and fight with him until he dies. For the second form, use the Magus Sisters' Overdrive and keep fighting until they die. If he is not defeated, then just use other Aeons.
alex_vandyck.

You will need a lot of Silver Hourglasses and Shining Gems. Also, have the Use ability for at least two players. Use a Shining Gem on Jecht, then for your other player use Silver Hourglass. Jecht and the blocks will not be able to move. It is now your turn again. You can also use this tactic on other monsters.
Sword Master.

Defeating Cactuars:
Provoke Cactuars them with Tidus, then attack with Wakka. If Wakka is not strong enough to kill the Cactuar with one hit, you will probably have to revive Tidus.

Make sure you have the two Summoners with Dark Ixion standing there, Just behind the save point and the tower are some mounds and crater-like "O" shapes. Keep running up and down near the right hand side of them to get Cactuar battles.
Jordan Craw.

First, have Rikku steal Bomb Cores from the Bombs in the Al Bhed home. Then, travel back to the desert and have her use one on the Cactuar. Bomb Cores are much stronger than Grenades and can kill a Cactuar in one hit.
Paris N. Wilson.

Use Rikku's grenades. It should take away 300 HP. They have about 600 HP total.
Raditz1325.

Defeating Cactuar King:
Note: This trick requires a strong Anima (over 12,000 HP) and Tidus' Blitz Ace Overdrive. Before entering battle, get Anima and Tidus into Overdrive. Also, have a few Phoenix Downs. When entering battle, it is easier to summon Anima and use its Overdrive first. Then, once Anima is killed or you dismiss it, use Tidus' Blitz Ace (get a Great). If this does not kill it, use Bahamut's Impulse or another powerful attack that does not easily miss.
SmeBodyUKno.

Defeating Chocobo Eater:
This trick requires Yuna's Two Aeons, Valefor and Ifrit. his creature has 10,000 HP. When the battle starts, your characters will have one turn to themselves.You do not have time to switch them back and forth. If you get Auron into the battle, have him use Power Break, then get Yuna and summon Valefor. Note: Have Valefor's limit bar full, then cast your attacks. This send it down about 2,500 to 3,000 HP, which will now drop it to the 7,000 range. Keep fighting until Valefor dies. Then, summon Ifrit and use your fire attacks. Every time you get hit, you should restore. To do this, cast the element that that summon has. Valefor cannot be restored. Ifrit can because he is fire. Cast the element on him, and about this time you will have a full limit bar. Keep repeating this and you will have a full bar almost every time you complete one Hellfire move. Restore your health with the element your summon has, and keep restoring until their health is full.
Logan Anderson.

Defeating the Crawler Machina:
Make sure that Rikku's Overdrive gauge is almost full and you have an Arctic Wind equipped. Have Auron, Rikku, and any other character out on the battlefield. Do not destroy the Magic Blocker that the Machina sends out. That prevents the Machina from using Mana Beam. Instead, have Rikku steal from the Machina to get a Lunar Curtain. Have the next two characters in your party attack. When Rikku's overdrive gauge is full, have her mix the Arctic Wind and the Lunar Curtain. This will cast Haste and Shell on your party. It also puts a shield around you. Also, your party will regain health after you are attacked by the Machina.
matt simon.

Crawler Machina has 16,000 HP. Hit him down to 13,000 HP then kill the monitor next to it with Rikku's Grenade or Arctic Wind. Make sure you have Velefor, Ifrit, and Ixion's Overdrive up. Start by using Velefor's Overdrive, then Ifrit's followed by Ixion's. By the time you have used their Overdrives Crawler Machina should be down at least 1,000 HP. Also have Rikku's Overdrive at the start of the battle to make it easier.
HippoHamster.

Use Steal and it will die.
stephen van cauwenberghe.

Defeating Dark Flans:
Use a Zombie attack then a Phoenix Down on it.
KingLink1421.

Capturing Dark Flans:
Use a Zombie attack at your first chance. Whenever it tries to use White Wind or Drain, it damages itself. After it uses White Wind, which will cure it of Zombie status, just cast Zombie again.
KingLink1421.

Defeating Defender X:
Before fighting Defender X, get all of your Aeon's Overdrive and also Yuna's Overdrive. After using Yuna's and your Aeon's Overdrives, Defender X should have 8114 HP remaining. If Auron does at least 1000 damage per hit, it should be an easy fight.
LPaul22123.

To flawlessly defeat Defender X, use Provoke. He will use Rocket Punch, which cannot kill you.
Yvl9921.

Defeating Defender Z:
To defeat Defender Z in Zanarkand Ruins, you need Tidus' Provoke. Use Provoke, and after that just attack normally with other party members. After being provoked, the only thing he will do is a Blast Punch attack to Tidus, and it will not kill him. It will only damage half of Tidus' HP on every attack.
Kubo.

Defeating Don Tonberry:
Have any of your Aeons that have 255 Defense, 255 Strength (or enough to do 99,999 damage with each hit), over 12,000 HP and their Damage Limit broken (9,999 goes to 99,999). Don Tonberry will never move forward; he will always use Voodoo. It is suggested that you also have the selected Aeon learn Haste. As soon as the Aeon is summoned, check how many turns you have before the Boss'. If it is one, use Shield. This will quarter the damage Voodoo makes. After his turn, use Haste. You will have over two turns before Don's. You can always check by selecting Haste and not confirming it. If it is over two, use Haste. After you have used Haste, keep attacking until it is your last turn, then use Shield. Repeat this until it dies. Only Anima's and the Magus Sisters' Overdrives are worth being used. However, only use them if you have one turn even after it is used.
Boris Guyon.

Defeating Extractor/Al Bhed Gunner:
Start with your entire party, including your Aeons, in Overdrive. Make sure that Tidus knows Cheer, Yuna knows Pray, and Lulu knows Reflex and Focus. Start with Rikku, Kimahri, and Wakka. Use their Overdrives against the Extractor, and not the floating Negator. Then, switch them out for Tidus, Auron, and Lulu. Have them use their Overdrives and switch Tidus for Yuna. Have Yuna use Pray, Lulu use Reflex, and Auron attack. Keep this up until the Extractor has about 6,000 health remaining. Then, just attack the Negator and have Yuna summon her Aeons to finish the battle.
Jay Jarodiya.

Defeating Evrae Altana:
Use two or three Phoenix Downs on it to kill it instantly when underwater.
Jason Chiu and Gavin Darklighter.

Use an X-Potion for a one hit kill while fighting him underwater. This does not work on the airship.
Barry.

When on the airship, you will face Evrae for the first time. He is intimidating with his poison breath and big size. At the start of the fight, try to get Rikku in. Her normal attacks are weak against him, even grenades. However, if you teach her Spare Change and work up a lot of money, you can actually defeat him with at least three hits from Rikku with money and Tidus and Auron attacking regularly. This will result in an easier battle and quicker ends. However, be ready for the next few batches of battles afterwards at the wedding.
FujisakiiSuguru.

Have Auron attack, Tidus use Haste (or Hastega), and Rikku Heal and use "Spare Change". Make sure that Auron can do attacks with damage over 1000 HP. His Shooting Star Overdrive will do over 4000 HP damage if done very quickly.
pieter moonen.

Before you battle, make sure you have Wakka, Tidus, and Lulu available. When the battle begins, use Scan with tidus. Then, let Lulu use Fira and wakka use his regular attack. When it is Tidus' turn, use the Pull Back command. Continue with Lulu's Fira and Wakka's attack. When the ship pulls back, switch Tidus and Rikku. Use her Al Bhed potions to heal and continue attacking with Wakka and Lulu. When Evrae moves in to attack, switch Wakka with Auron and use his regular attack until it dies. Note. When it uses its toxic breath, use Al Bhed potions.
drewwuzzhere.

Get to about level 45, have about 10 Softs, and have Tidus, Wakka, and Auron available for your party. Start by casting Slow on Evrae. Keep attacking and using your Overdrives until Evrae inhales. When he inhales, have Cid pull back. Keep attacking with Wakka and heal your party. This is the only time you can Heal without wasting turns. When Evrae does his Poison Breath, it should dissipate before it touches you. After that, keep attacking him with your Overdrives and regular attacks.
Brian.

When Evrae's HP is somewhere between 10,000 and 8,000, make sure Kimarhri knows Self-Destruct. Also Evrae, should be close to the airship. Make sure Kimarhri's Overdrive is full. Make him use Self-Destruct on Evrae. It should take out about between 5,000 worth of damage. If you are lucky, it might do almost 9,000 worth of damage to Evrae. Then, just finish him off with Wakka's ball or Lulu's magic (recommended). Using Tidus is also good, as long as he is holding the Brotherhood weapon.
fabu5.

If Lulu does not have the third stages of Black Magic (Firaga, etc.) or Tidus does not have Hastega, keep training in the airship, Try to have everyone get into Overdrive. Then, get at least 40 Antidotes. Make sure that Rikku has enough Al Bhed potions and 30 Softs. Go out the dock. Keep Rikku and Tidus in the party at all times unless Evrae moves away. Bring Wakka, Lulu, and Kimahri in until you or it comes back. Haste or Hastega everyone. Tell Kimahri to Lancet. If Evrae comes back, bring Tidus and Rikku in. Also, slow Evrae. If it hastes itself, leave it alone. Once it breathes, move away if you cannot face very strong poison and damage. Nearly at the end, use their Overdrives. If its HP is about 2,000 then use Auron's Shooting Star. You will get an Overkill if he is strong enough. You will get two Black Magic Spheres. Save four of the Black Magic Spheres for Yuna to have the Firagas, Blizzagas, etc.
kutexchunsa.

You need at least fifteen Al Bhed potions, Kimari's, Tidus', Lulu's, Rikku's, and Auron's Overdrive, and Kimari must know Self Destruct. Before you start, make your first three characters to be Lulu, Tidus, and Rikku. When you start the battle, pull back. Once this is done, Evrae most likely will have atacked. Use an Al Bhed Potion. With Tidus, use Haste on everyone and slow on Evrae. With Lulu, use Blizzara. Have Tidus use Cheer and Rikku use Luck, unless someone lost lots of health; then you should use an Al Bhed potion. Continue this until Evere uses Swooping Siyth. Then use everyone's except Wakka's Overdrive. Make sure you use Kimari's overdrive last and you will use Self Destruct.

To defeat Evrae on the Airship, make sure you have 29 High Potions, 50 Phoenix Downs, 1 Ether, and lots of gil. He is very powerful and uses his poison breath. At the start, move the airship back and use Wakka, Tidus, and Auron. Have Wakka attack with his Blitzball; have Tidus use Slow and Scan on Evrae, and Haste and Cheer on Auron. Then, have Auron heal them with High Potions if they become hurt. As soon as the first digit on his HP is 1, make the airship get closer. He will use Haste on himself. Switch Wakka with Rikku and use Power Break with Auron and use an Overdrive if possible. Make Rikku use Spare Change with all the money you have and Tidus use Delay Attack. Keep doing this until Evrae is defeated.
Boe leonheat.

Get as many Al Bhed Potions as possible, as well as a few Antidotes and Hi Potions. Have Tidus, Auron, and Rikku in your front line. Tidus needs to cast Haste on everyone and use Cheer five or six times. Have Rikku steal two Watergems from him. Then Mix/Use the Water Gems. Pull Back can save you from Poison Breath. After you Pull Back, Heal, and once every two times you Pull Back, wait for the missiles. Tidus and Auron can attack and use Overdrives. Rikku can Steal/Use or Heal. He is a difficult Boss. You get a Blackk Magic Sphere for defeating him. To defeat him underwater, use two Phoenix Downs because he is in Zombie status. You will get another Black Magic Sphere.
Val Ammer.

Before you start, make sure that you have a lot of Al Bhed Potions. You should have a lot of them from Bikanel Island. If not, you are certainly due for a much more difficult battle, and should prefer battling from afar, using Potions and Hi-Potions with a character in Haste every turn that he gets. However, unless you used them all, you should have plenty remaining. First, there are two locations that you can fight Evrae from; near and far. You will start near. To go far, have Tidus or Rikku use "Pull Back", a Trigger Command that only they have. When you are up close, there are a few things to do. Starting preparations while up close. Have Auron use Power Break. This will halve the damage Evrae does with his regular attack and his Swooping Scythe. Allow Wakka to use Dark Attack or Dark Buster every once in awhile so that he almost always misses. Try to have Rikku Steal, then Use, a Water Gem for about 1,500 points of damage, or Steal and Mix (Overdrive) two for 2,000 points of damage. Whether or not you choose to stay close or go far, try to have Tidus use Slow on Evrae. It misses very often, but you should get it in three to five tries. Should Evrae's physical attacks manage to hit you, they will only do 600 points of damage (as opposed to 1,200 originally). Because he is slow, you will be getting a lot of turns in. Use the following strategy for battling from afar. This strategy is probably easier to win with. Notice that Cid is now in the Turn Chart. If you have used "Pull Back" before his turn, on his turn, he will move away from Evrae. The only way to hurt him now is with Wakka and Lulu (who you should Haste with Tidus). However, his attacks are much less threatening. While far away Evrae will usually use Photon Spray, which is an attack composed of about ten randomly-aimed hits that attack for around 100 points of damage. Most likely each character will lose around 300 points of damage. Every two turns Evrae gets, have Rikku use an Al Bhed Potion and you should be fine. If you have not told Cid to "Move In" (brings you back near to Evrae) and you are still far away from him, on Cid's turn he will use "Guided Missiles". This will hit roughly fifteen times for 200 points per missile (about 3,000 points total damage). He will only do this three times before running out of missiles and just do nothing. To hurt Evrae from afar, have Wakka either attack (750 points) or use the Black Magic "Drain". Evrae will lose about 500 HP and Wakka gains it. Have Lulu use her second-level spells (Blizzara, Fira, Thundara, Watera) for about 500 points of damage. Lulu's Overdrive will hit Evrae, but Wakka's will not for some reason. Evrae may use an attack called Swooping Scythe, which hits everybody for 600 damage (or 300 if you used Power Break). However, this also has the same effect as "Move In", as you are now near him again. You can "Pull Back" again and repeat (which is the easiest, yet longest, way to win). You can remain battling near, if you are less patient and feel that you have a strong party or are very good with the battle system. Auron can hit him for about 1,000 (2,000 critical) damage each time, all Overdrives will be in reach, and you can basically just hit him in each turn you get, as opposed to waiting a lot. Because you have already taken care of his regular attacks, Evrae will either miss or do relatively low damage (yet high compared to what he does from far away) to a character most often. Should he hit, you can use a Hi-Potion, Al Bhed Potion, or just ignore it. He will occasionally use Stone Gaze, which will petrify a party member (but will not do any damage). This basically is the same thing as the having the character die, and if all characters are petrified, you will lose. Immediately cure this with either a Soft or an Al Bhed Potion. The biggest problem you will have, however, is his Poison Breath. He will first inhale (he takes a big breath), which does no damage or anything to you. However, on his next turn, he will use Poison Breath. His inhalation is just a warning, basically. Poison Breath will hit each character for 1,500 to 1,800 points of damage and inflict Poison status on everybody. Anyone that survives will be weak and be poisoned. Should Tidus or Rikku select "Pull Back", and Cid pulls back, Evrae's Poison Breath will miss. You will have to use the turn chart to be able to plan this accordingly. This is the only way to avoid Poison Breath. To explain it best, if the turn chart order goes: 1. Evrae - Inhales, 2. Character, 3. Cid, 4. Evrae, you will probably be able to avoid it. Should your character be Tidus or Rikku, you can use "Pull Back" (tell Cid to pull back). Cid will then actually will pull back, and Evrae's Poison Breath will miss. If it is not Tidus or Rikku, then switch in for one of them and use "Pull Back". If you have both Tidus and Rikku out and it is the third character, then you cannot avoid it. For this reason, it is wise to never have both Rikku and Tidus in at the same time. Note that you always lose if the scenario is: 1. Evrae - Inhales, 2. Character, 3. Evrae; or 1. Evrae - Inhales, 2. Cid, 3. Evrae. There are ways to increase your chance of the first scenario. First, have Tidus use Haste on any characters you will be using (Tidus, Rikku, Auron, and Wakka probably). Also, have Tidus try to use Slow on Evrae. If Evrae's turn is just before Cid, or you could avoid Poison Breath with just a couple extra turns, have Tidus use Delay Attack for a couple extra turns. Note that Tidus will always have his next turn immediately after Evrae, so you cannot use it twice in a row. Finally, if you can kill him before he uses it, then do so. However, chances are that Evrae may get to use it. When he does, have Rikku use an Al Bhed Potion, or if sheis dead, have each living character use an Antidote on himself and then revive Rikku. If he can survive the Poison's damage (probably only Auron), then you can try reviving Rikku first. The Al Bhed Potion will remove everybody's Poison and give them 2,000 more HP. Try not to get hit though, as this is risky especially towards the end. After Evrae's HP drops below 10,665 (Split Infinity), he will use Haste on himself. If you use Slow on him, he will instantly use Haste again (it does not have to be his turn). Do not waste your turn by doing this. Before this happens, it would be wise to have each of your characters in Haste. It would also be wise to "Pull Back" repeatedly. Evrae will always use Swooping Scythe as a counter now, but if you keep moving back, using Delay Attack, using Wakka or using Lulu, you should be all right. If you cannot get back in time even with delay, try Auron and see if you can finish him. If you do not want to do this, then make sure Evrae is in Dark status (Wakka); after Poison Breath he canot finish your whole party at once, although he may use Stone Gaze. It is recommended that you finish him with Wakka and Lulu in Haste from afar. Note: If he inhales and you "Pull Back", do not hit him. He will counter with Swooping Scythe then finish you with Poison Breath. One last problem you may encounter is Evrae using Haste early. He may do this after being hit repeatedly by Delay Attack. Do use Delay Attack twice in a row if you are encountering this.
alex g.

Use the following trick to get your party out of Evrae Altana's reach. When the Boss battle first starts, do not attack Evrae. Instead, check Tidus' and Rikku's trigger commands for a command that reads "Open lock". Use the commands to open the locks on the gate behind the party. As soon as the gate opens the party will swim away from Evrae and Evrae will follow them. You will enter another room similar to the last one, with a locked gate behind the party. Once again, use the trigger commands to open the locks and the gate itself. As soon as the second gate opens, the party will once again swim away and Evrae will follow. However, this time the gate will shut before Evrae can get through. If you paid attention to the information window between turns you should notice that it says something similar to "Evrae Altana can't strike back" on Evrae's turn. You are now out of its reach. Note that the boss is a Zombie. Hit it with a few Phoenix Downs to easily defeat it.
Ezeldachamp.

Defeating Giant Turtles:
Use Petrify.
Gary Hodson.

Defeating the Holy Ground Dragon:
In the fight with the dragon immediately before you get to the Zanarkand Ruins, cast Reflect on him. If you do not have the Reflect spell yet, you can steal a Star Curtain from an Mandagora using Rikku. They are in the cave immediately before the fight. Then, use that item on the dragon. He will no longer be able to heal himself or use Protect.
jacksonbryant.

Defeating Iron Clad:
Have Tidus, Yuna, and Auron with their best weapons and Overdrive on Victor. Fight a Dingo twice at the Monster Trainer to get Overdrives maxed. Fight Iron Clad with Celestial Weapons maxed out. Use Auron's Overdrive Banishing Blade. This causes Armor Break. This is important, as it always works unlike the normal Armor Break which only has a 5% chance of working. Then. use Tidus' Overdrive Blitz Ace. This should do 99,999 damage every hit because of Banishing Blade. Next, use Yuna's Overdrive to Grand Summon Anima. Use Anima's Overdrive to finish off Iron Clad with an overkill and get 2 HP Spheres.

Defeating Jecht:
His first form only has 60,000 HP. His next form has 160,000 HP, and his Ultimate Jecht Shot is extremely hard to survive if the Protect spell is not cast on all characters. When Rikku's Override gauge is full, mix Light Curtain and Light Curtain to create Super Mighty G. It casts Protect, Haste, Shell. and Regen on all characters. It is also recommended that all characters have Auto-Med as one of there abilities. Only summon Aeons when Yuna's Override gauge is full. Jecht, when fighting Aeons, will attack more than three times after the Aeon's turn. Double casting Ultima and Holy is also extremely useful in this battle.
DemonStar.

To defeat Jecht, all you need to do is have Anima. He should have an HP gauge of at least 10,000. Just attack or Pain all the time. When you get Anima's Overdrive, use it. At this point, Jecht is sort of weak, and the Overdrive will kill him.
AuronsBabe.

Defeating Kottos:
It is possible to defeat Kottos without extensive stat maxing. Kottos seems to target the character with the highest Strength stat from those who are still alive. You must have Yuna's Celestial Weapon fully powered. Place Tidus and Yuna in the starting lineup. Use Lulu as the third character if you have Doublecast, Flare, or Ultima, and the Onion Knight at full strength. Have Tidus cast Haste on Yuna on the first turn. After that, defend or use support skills every time his turn comes up. Kottos counters everything with what will no doubt be a one-hit kill at lower levels, and you want Tidus alive for when it actually gets to Kottos' turn; with this lineup, he always goes after Tidus if possible. Have Lulu cast her best spells. Yuna will be casting Life constantly, but you should eventually defeat the Boss this way. Note: This may take some time. You can probably switch out Tidus at some point for some other character such as Auron or Wakka; again, high Strength so they are the one getting attacked. This can be useful for gaining some extra levels if one of those characters has a weapon with Overdrive to AP on it (obviously, use the Stoic mode.)
Artscrafter.

Defeating Malboros:
There are a few options to defeating Malboros. One is to have a party member out that has an armor customized with Confuse Ward, Poison Ward, Berserk Ward, and Dark Ward. Your second choice is to customize a character's weapon with First Strike, other than Yuna's, and have that character out. When you are ambushed, the character with the First Strike weapon will be able to go before the Malboro. Note: Make sure you do not have Yuna out yet. Switch the character with the First Strike weapon out with Yuna and Summon (Grand Summon). The best choices to summon are Valefor or Shiva. You can use Valefor's Sonic Wings or Shiva's Heavenly Strike continuously. The Malboro will not be able to hit you, insuring victory. If you decide to use another Aeon, use Yojimbo or Magus Sisters. Yojimbo will dodge almost all the Malboro's attacks and they are three Aeons in the Magus Sisters, making it harder for the Malboro to kill them all. A good thing about using Aeons against Malboros is that they cannot use Bad Breath, since Aeons are immune to all status abnormalities.
Andrew Meza.

Use Aeons except for Shiva. When you use Ixion, use Thundara on yourself when he gets to the yellow limit. Use a many Overdrives as possible. When your Aeons are out, he should have about 1,000 to 3,000 or more. Then, just attack with Auron. Note: This is useful when trying to capture it for the Arena.
GamerPr6.

Defeating Nemesis:
At the start of the battle, summon Yojimbo. Pay as much as you can (about 10,000,000 or more gil). If he uses Zanmato, he will instantly kill Nemesis even if his HP is about 10,000,000.
Edric Solis.

It is possible to defeat Nemesis raising only two stats and without Zanmato. Raise Kimahri's Agility to at least 230 and his MP to at least 300. Give him Auto-Haste armor and a First Strike and One MP Cost weapon. You can even have all Kimahri's other stats and everyone else's stats at No Sphere Grid level, as long as Kimahri's Agility is 230+ and he has Auto-Haste armor and First Strike and One MP Cost weapon. Also teach him the Auto-Life White Magic and his Doom Overdrive. He must have full Overdrive at the start of the battle. Use Auto-Life, then Doom. Nemesis will counter with Ultima. You should get one more turn before Nemesis' turn. In that turn, cast Auto-Life on yourself. Then, Nemesis will keep killing Kimahri; just keep casting Auto-Life on yourself. Eventually, because of Doom, Nemesis will die. If you get any extra turns, you can use Mug (not Steal, as Nemesis will counterattack with Ultima) to get some easy Level 4 Key Spheres -- however you will probably be too busy casting Auto-Life. If it gets too boring, have the cursor set to "Memory" and use a controller with an auto-fire feature to keep casting Auto-Life. If you cannot get it to work with Kimahri, then give Yuna the above equipment and stats, and give Kimahri First Strike so he can use Doom. However, make sure to cast your first Auto-Life immediately at the start of the battle, then Doom immediately afterwards. This strategy also works with every other Monster Arena Boss except Shinryu.
steaver370.

Cover the entire Sphere Grid with Yuna and any two others. Make sure you have Break Damage Barrier and HP Barrier. Use Hastega. Then, Quick Hit with everyone repeatedly. When you select Quick Hit with Yuna, before you choose the target make sure she will have another turn before Nemesis attacks. If it is Yuna's last turn, do not do Quick Hit. Instead, summon any Aeon. Nemesis will attack and most likely destroy the Aeon. Go through all your turns doing Quick Hit, and summon on Yuna's last turn. Go through this process repeatedly until he is defeated. You will probably have two or three Aeons remaining when he dies. If your attacks do not do 99,999 damage, than you should get more strength first. Do not use Overdrives. He counters them with Ultima. Every time you defeat him, you will either get armor that has Break HP Barrier or a weapon that has Break Damage Limit.
uttersilence89.

Defeating Omega Weapon:
Use Kimahri to use Lancet. He will learn the Overdrive Nova. Use Nova and get Yuna to summon Magus Sisters. Use their Overdrive, then use there special attacks which are Passado, Razzai, and Camiside. Keep doing this until Omega Weapon is defeated. Use same strategy on Ultima Weapon.
Mooncodan.

Train the Magus Sisters until Cindy and Sandy are about 20,000 HP and their Overdrive gauge drive is full. First, use Kimari's Lancet on Omega then summon the Magus Sisters and use Delta Attack to do 99,999 damage.
Joseph Burns.

Use the Magus Sisters and all your problems will be solved. The Magus Sisters are extremely powerful, but have some problems. You cannot control exactly what they do, and sometimes they will just "take a break". You can also use them to defeat Sin.
Shibbykid788.

To find Omega Weapon and Ultima Weapon you must explore the ruins with a No Encounter ability on one of your characters (Peaceful Bangle, Ductile Rod, etc.). The best way to find them is to have a high level. When you enter you will be tempted to go straight. Instead, go to the left and then straight. The rest of the way should be obvious.
FinalFlashX.

Have your three fastest party members (except for Yuna or Kimahri) in the starting formation. Use your first party member that can move, but not Yuna or Kimahri, to swap out for a member who can steal. Steal the 30x Gamblers Spirit from the second Weapon. Use the second member to swap for Kimahri and use his Lancet skill to acquire the blue magic "Nova". Then, use the last party member to swap for Yuna and summon the Magus sisters with a full Overdrive. After about one Overdrive and two Razzia's, the Weapon should be defeated.
Armin Ruf.

When you go through the Omega Ruins to get to Omega Weapon, make sure you are decently leveled up, but not too much. Before you start your conquest, get used to the fiends there. Get into some battles to see what you are up against. When you gom you should have Auron's, Yuna's, Tidus's, and Kimhari's ultimate weapon maxed out. Take a left when your start off, then walk up for a bit. Open the treasure chests at your own risk. Then, keep walking forward. Take a right turn at the intersection then continue forward. You encounter a fiend called Ultima Weapon. Use Tidus's or Auron's Overdrive then finish him off with Holy. Ride the Teleport Glyph up and walk. You will encounter a decent amount of enemies. It is easier to just flee. You will then encounter Omega Weapon. Start with Auron, Tidus, and Yuna in your party. Do a normal attack with Auron. Then, Grand Summon Anima. If you are leveled up, he will do around 90,000 damage. You can then finish him off with Pain or dismiss him so that Tidus can get some AP. It is easy if you just flee all the battles in the ruins or even better, have the No Encounter ability.
One Wingged Angel.

Defeating the Sanctuary Keeper:
Have Yuna cast Reflect on the creature. Then have your highest hit point character hack away at it. It will still cast the Cure and Regen spells, but with Reflect it will be healing the party instead of itself.
Jim Phoenix.

Get your Overdrives full on every character and Aeon. Next, cast Reflect on the Boss. Every time he uses curing magic, it will heal the party. Then, use Kimari's Mighty Guard and summon your best Aeon (Ixion then Shiva recommended). Magic is useless in this battle because the Boss has high magic defense. It also does a bad move that inflicts lots of bad status effects (even death). This is a fairly easy battle if you have over 3,000 HP and a good defense. You should also have over 5 X-Potions, 10 Phoenix Downs, some Ethers, good curing magic, and Regain, Shell, and Protect.
RBondoron.

Start the fight with Tidus, Yuna and Auron. Cast Hastega and Protect on everyone and use Auron's armor and Mental Break attacks against the creature. After breaking its defense , switch Auron for different fighters. Remember to cast Haste and Protect on each new party member you switch in. Cast Reflect on the creature, then summon Aeons that are already in Overdrive mode. Each Aeon will only get one shot because the Sanctuary Keeper will use Mana Breath to eliminate them. After the Keeper loses half its HP, it will use Curaga on itself. However, if you cast Curaga on it one of your party members will receive a well deserved reward and the creature will receive nothing. Beware of this Boss' attack pattern. It starts with Photon Wings, then two regular attacks, Mana Breath, then two Curagas. It will also sometimes counter with a Tail Sweep. It is important to protect your party from status affects -- equip them with armor that protects them from Sleep, Silence, Darkness and Confusion.
Josh Steeves.

Have Tidus, Yuna, and Lulu (with Bio learned) in your party at the start Have Tidus cast Hastega first if you have it, then Lulu cast Bio. Next, have Yuna cast Reflect on Sanctuary Keeper. This way, he cannot counter with Esuna or Protect on himself. Once Lulu is in turn, switch to Auron and do Armor Break. After that, have Tidus use Haste on Auron. Have plenty Holy Waters and Remedy available because of his Photon attack which causes 750 to 1250 HP damage and imposes a number of status ailments on the party, including Curse (disables the Overdrive ability). While Bio drains 2000 HP out of Sanctuary Keeper on every turn, make sure Yuna is kept alive if you have no Phoenix Downs. If you do have Phoenix Downs, concentrate on keeping your HP up. Be careful of Sanctuary Keeper's Mana Blaster attack, which will deal around 3000 to 3500 HP damage. With Bio doing its work, have Auron and Tidus deal physical blows while Yuna heals the party. If Sanctuary Keeper casts Reflect any member of the party, have Yuna cast Dispel, since he knows that Reflect has been cast on him. After all the physical attacks by Tidus and Auron and with Bio draining the HP out of him, he should be easy to defeat.
Collin Beishir.

Have Tidus, Yuna, and Lulu in your party. Make sure Tidus knows Hastega, Yuna knows Reflect, and Lulu knows Bio. First, have Tidus use Hastega. Then, have Yuna cast Reflect on it. This should prevent it from using Curaga or Esuna on itself. Also cast Reflect on Lulu so that she can cast Bio on herself, which would be reflected onto it. This should keep a constant 2,000 damage on it for the remainder of the battle. Keep hacking away with Tidus and use Yuna to cure when it uses Photon Wings. If it does Esuna on itself, it will cure you instead. If you have to, switch Lulu out with Auron and cast Haste on him.
Andrew Mardonio Meza.

Defeating Seymour 1:
In the first fight with Seymour, have Rikku steal from the two guards. This will stop them from using Auto-Potion. Seymour will call Anima, and an Overdrive gauge will appear in front of him. Attack and watch the gauge, When it is almost full, have Yuna call one of her Aeons to take the hit from Anima's Overdrive. Repeat this as needed. After defeating Anima, Seymour will start casting multiple spells. Use Yuna to heal you party, and have the rest attack.
jstemple and FinalFlashX.

When you fight Seymour for the first time, and after he summons Anima, you will have to fight just him. Seymour's magic attacks follow the exact pattern of Ice, Thunder, Water, and Fire. Therefore if you have Yuna cast her Nu-spells, you will not get hurt at all.
Lou Paniccia.

Scan Seymour with Sensor, then click on Seymour and see what order he casts his magic in. When you have learned this order, have Yuna cast the NulShields in the same order and he will never hit you. Every time you try to hit Seymour, one of his Guado Guards will jump in your way, and every time you hit a Guado Guard, he heals himself. To take out the two Guado Guards, use Rikku and your best hitter. Have Rikku to steal from one of the Guards and then have your best hitter attack that Guado Guard. You will get one Hi-Potion and the Guado Guard will not heal. When the Guards are dead and Seymour has exceeded his life, he summons Anima, an Aeon. You have seen Anima at the Blitzball Tournament. Use Yuna to summon the "????" Aeon, whom is Shiva. Use Boost for Shiva twice. This will put her into Overdrive. Before you use Diamond Dust (her Overdrive), heal yourself with Blizzard/Blizzara. Repeat this twice and Anima will die. Quickly dismiss Shiva. To defeat Seymour again, just cast the NulShields in the order of his magic and attack with your best hitters; or use Lulu, for Black Magic.
xbosouthiex.

Have Yuna learn Reflect and cast it on all of your party members at the start of the fight. Use a weapon with Stonetouch (such as Auron's Gorgon Gaze) to dispatch the Guado Guards. Beat down Anima with the "????" summon (Shiva) by using Boost to charge her Overdrive twice and healing her with Blizzara. Then, let Seymour kill himself by casting his multi-spells on the Reflect. Each time the spell will bounce back on him and deal over 1500 damage. Since he only has 6000 HP, the battle will end quickly.
UnholyFigure.

To defeat Seymour 1's guards quicker, charge Kimarhi Overdrive and use Ronso Rage-Stone Breath. It will automatically kill the guards, however Seymour is immune.
Rubberturkey.

Make sure that Yuna is in your attack party. Use her to cast NulBlaze, NulShock, NulFrost, and NulTide. Seymour and his Guado friends only use magic attacks and Confusion. Keep doing this until Yuna Reaches overdrive and use her "Grand Summon". You can use what ever Aeon you wish, but Ifrit is recommended. He will be charged with Overdrive because Yuna was, will kill the Guados. Seymour will summon Anima. You should use Boost once, take Anima's attack (which will only take away half of your life). After that, use Fira or Blizardra on yourself, depending on whether you chose Ifrit or Shiva to fight (elemental Aeons gain HP from their elemental attacks). Repeat this until you reach Overdrive and use your attacks. When Anima's Overdrive gauge is almost full, use Shield and his Overdrive will only take half of your life away. Repeat this until he dies. You will have to fight Seymour once again. Do what was you done before with the Nuls and use either magic or other attacks.
John.

Have Tidus, Yuna, and Auron in your group. Have Tidus use Cheerm Yuna use NulShock, and Auron use Power Break or Armor Break, if you have it. Then, take out Tidus and put in Kimhari. Have him use a Potion if anyone needs it. When Yuna has all the Nuls, have her summon ???? or Ixion. Wait until they get Overdrives then have them use it. It should kill them and he will summon Anima. Always have an Aeon out. When it gets Overdrive, use it. If the Aeon gets low. have it use a magic attack of its own on itself (except Valefor because it will probably kill him). When Anima gets his Overdrive up, have the Aeon use Shield. Keep using it until he dies. You will then have to defeat Seymour. Keep attacking and you will have a good chance of winning.
simmons.

Have Yuna, Auron, and Rikku out. Have Rikku's Overdrive charged up, but do not use it. Use Steal on the guards, then kill them. Seymour will call Anima. Defeat Anima, then use Rikku's Overdrive and mix two Grenades to make Flash Flood. If he is not dead, then use Auron's power break.
kwalters.

Get Rikkus Overdrive and mix a Map and Grenade to kill Seymour with one hit. It should also poison him.
inu.

Have all characters in Overdrive. Have Knimari's Stone Breath, Lulu's Fira ability, and Tidus' Slice And Dice Overdrive. For a faster battle, have all Aeons in Overdrive. Also have two Light Curtains equipped and if desired a Lunar Curtain and an Arctic Wind. Start the battle by using Stone Breath to destroy the Guado. Next, have Auron use Shooting Star (if acquired). Then, pummel him with Fira. When he summons Anima, summon Ifrit (teach him Fira). Continuously use Fira and do not forget to keep Ifrit's health up. If Ifrit should fall, summon Shiva. Attack him with Blizzara. Each Pain attack will cause around 500 damage. When he is destroyed, dismiss Shiva and bring in Riku. Mix two Light Curtains. This castes Shell, Protect, and Regen. If Seymour does not get his attack in, bring in Yuna and cast Nul-Frost. To determine his magic pattern, cast Scan on Seymour.Cast the Nul-Shields in that order. Also if desired, try poisoning him. If he is not dead, bring in Wakka and use his Elemental Reels. Try aligning the red circles.
James Knight.

Have Rikku use a Petrifaction Grenade on all three opponents (Seymour and two guards). The guards should now be dead. Summon Ifrit, and use his Overdrive, Hell Fire. Use his regular attack after the Overdrive, then use Fira if HP gets low. Anima's attack (Pain) only does about 300 damage to your Aeon; use Fira every two hits that you take.
Str8cracker02.

Use this strategy if you want easier battles against Seymour. When fighting the Spawn Gui for the second time, have Seymour use Thundara on himself continuously until he dies. As a result, Seymour will not get any AP from the battle and be weaker later.
Tim Arneson.

Make sure that Yuna has her overdrive up before going to Macalania temple. When Seymour appears, you will have another Aeon with Yuna. Use Grand Summon on ????. About 10 to 20% of the time, ???? will have a critical hit and kill Seymour. Also, if Rikku has her Overdrive up, mix a Grenade and the Map to kill Seymour.
Nash Eric.

When fighting Seymour at Macalania Temple, use Rikku, Yuna, and Auron. Read Seymors stats of what attacks he uses, then have Yuna cast the spells in this order, Nulfrost, Nulshock, Nultide, and Nulblaze. It should keep your characters protected. Have Rikkku use Steal on his guards, then have Auron attack them. Only use Yuna for counter spells. After awhile, have Rikku use Grenades. Be careful and watch how much HP Seymour has remaining. When he gets under 3,000 of his 6,000, he will summon Anima. When this happens, have Yuna summon the ???? Aeon. Anima will then attack. Have Shiva (????) heal herself with Blizzara, then attack with Blizarra. Always have Shiva close to full health. When her overdrive is full, use it . She will have a chance of using in twice before dying. By then, Anima's Overdrive should be almost full. Summon your weakest Aeon, Valefor, to take the damage. Make sure to have Ixion's Overdrive full. Then, summon Ixion and use its Overdrive. Anima should almost be dead by now. Summon Ifrit and attack with Fire, and also heal yourself with Fire. After this, Anima should die. When attacking Seymour, keep Yuna casting the Nuls. Have Auron attack and RIkku use her items, as before. Seymour should be defeated after awhile. Have potions, etc. ready for use.
Hazukisho.

When facing Seymour for the first time, equip Reflect on your entire party. Seymour only uses spells, and will always end up hurting himself.
Neil Sen.

After you have summoned Shiva and are waiting for your Overdrive limit to fill, use both of Shiva's Null spells. After defeating Anima, usually Seymour will kill Shiva with the first spell he uses. He should use both of the spells you Nullified. This should fill your overdrive meter. Use your overdrive and it will kill Seymour.

Have Yuna and your two best hitters in your party. Have at least one of your strongest characters and Yuna's Overdrive gauge full. Note: Do not use Yuna's Overdrive to kill Seymour; save this for later. Use their Overdrives to kill the Guado Guards at the beginning of the battle. After they are dead, Seymour will just keep casting his Black Magic spells in the order of Ice, Lightning, Water, and Fire. Keep this in mind and have Yuna cast the Nul spells in the same order to prevent all damage to your party. Meanwhile, use your hitters to hack away at Seymour. When his HP starts to get low, he will summon Anima (the Aeon he called at the game in Luca), Use Yuna's Overdrive Grand Summon to summon your newest Aeon ???? (Shiva). Fight Anima until you get your Overdrive up, then use it on Anima. This will make his HP drop very low. Afterwards, Anima will use his Overdrive Oblivion. If this does not kill you, heal by casting Blizzard or Blizzara on yourself (Ice magic will heal the Ice Aeon) and fight Anima until Seymour dismisses him. However if Shiva dies, summon another Aeon until Anima is dismissed. You will now just have to deal with Seymour. Use Yuna to keep all of the Nul spells up to date as Seymour will now cast multiple spells (but still in the same order). Again, use your two best hitters to hack away at him until he dies. However, do not let your HP get too low -- you will have to face Guado Gaurdians and their fiends after they find out you murdered their leader.
Sweetiechika14.

Start with Yuna, Tidus, and whoever came next in your formation. Make sure that Rikku is traded in for the character besides Yuna and Tidus. On Tidus' turn, use the trigger command "Talk". On Yuna's turn, use Nulfrost. He casts his spells in the order of ice, lightning, water, and fire. Do not "Talk" yet. With Rikku, steal from one of the two guards on either side of Seymour. When it comes to Tidus, cast Slow on Seymour. On Yuna's turn, cast Nulshock and have Rikku steal from the other guard. When it is Tidus' turn again, cast Haste on Yuna. You can now talk with Yuna when you have the chance. Next, cast Nultide with Yuna and switch Rikku for Auron. Have him attack the left guard. This should do about 200 to 300 damage. Use Tidus to attack the right guard. This should do about 500 to 600 damage. Make sure Yuna keeps casting her Nul spells in order throughout the first part of the battle. When both guards are defeated, attack Seymour with Tidus and Auron. This should only take a few turns. He will then call forth Anima (the Aeon you saw at the Blitzball tournament in Luca). He has 18,000 HP. Have Yuna use her Overdrive (it should be up) and summon "????". Use her Overdrive and attack normally while healing yourself with Ice spells. If "????" dies, bring out Ixion. and do the same thing; attack normally and heal. Anima should die fairly quickly with this strategy. When you fight Seymour again, it is the same strategy as when you fought only him in the first part; attack with Tidus, Auron, Wakka, Lulu, Kimahri, and Rikku. Switch them out, but make sure that it is before Yuna's turn. This will make it so that everyone gains experience. Seymour should die fairly quickly
Josh.

Defeating Seymour 2:
Cast Reflect on all party members and Seymour will heavily damage himself with his magic.
OkThatsNice.

Cast Reflect on Seymour (not his pet), then keep attacking his pet. The pet will take life from Seymour and cast Curaga on him, which will reflect back to a party member. Use your Aeons' Overdrives to kill him faster.
FinalFlashX and Butiki68.

Make sure Yuna knows Reflect, the 4 Null-spells, Protect, and Shell. For Tidus, make sure he has Haste or Hastega to speed up your party members, as well as Cheer to increase power and defense. Also, before the fight, make sure each member and Yuna's Aeons are in Overdrive to inflict greater damage. Each member should have over 2,000 HP, because Seymour casts powerful magic. If you have Wakka powered up with good strength from the Sphere Grid, his attacks should cause about 2,000 to 3,000 damage to this Boss. Equip some Hi-Potions, Phoenix Downs if needed, and status effect removers in the event they are needed. Start with Yuna casting her Null Spells to protect against Seymour's strong magic spells such as Multi-Blizzara, Watera, etc. in which his magic hits the entire party in several shots and causes over 1,000 damage to each member. Also have Yuna cast Shell and Protect on the party, to stand up to the Mortibody's attacks. Then, have Tidus cast Haste or Hastega to make a member have more turns to attack. Get your heavy hitters out, such as Auron or Wakka to lay some damage down on the Mortibody. When the Mortibody is low on HP, it will steal about 3,000 HP from Seymour. However, this means you need to deplete the Mortibody's HP again. To steal HP, have Yuna cast Reflect on Seymour, so when the Mortibody steals HP from him, it will transfer it over to you instead. Eventually the Mortibody will keep draining Seymour of HP, and you can use your members' Overdrives to hit on Seymour as well as the Mortibody. Your Aeons only get one chance to attack before Seymour finishes the Aeon off -- make sure they are all in Overdrive. When Seymour is killed, the Mortibody will die as well.
Ztegge.

Have Yuna Cast reflect on each character. Then, use your strongest physical attacker use their Overdrive. Next, use LuLu to take down Seymour. It does not matter if he hurts you with a physical attack as you can just use a Phoenix Down if you die. Note: If you do not have Reflect, just cast Nulspells.
Nickz2234.

Make sure that Yuna has her Overdrive, and Tidus and Lulu are out at the beginning of the fight. Have Lulu cast Bio to poison Seymour. Have Tidus cast Hastega to make your party faster. Have Yuna Grand Summon Bahamut and use his Overdrive. Then, instead of attacking, he will use Break. Bring in the heavy hitters (Auron and Wakka). You must remember two things: do not switch out Tidus; and do not attack Seymour or his spirit thing will permanently kill one of your characters until the end of the match. Have Tidus cast Hastega again and the match will be easy. Wait until the spirit thing uses Cure on Seymour, then attack until you win. Everyone should gain a lot of AP and you will end up in Macalania Forest again.
SamAndDJ02.

Have Yuna in your party at all times. It is highly recommended that you start with all your Aeons and characters in Overdrive. Start with her, Wakka, and Tidus. Have Wakka use his Overdrive and Tidus Haste Yuna, then switch them for Lulu and Kimahri. Have both of them use their Overdrives, then switch them for Auron and Rikku. Auron should use Armor Break and Mental Break, and Rikku should steal from both. All this time, Yuna should cast Protect and Reflect on herself and Heal and cure status ailments. Once everyone except Rikku and Auron have had one turn, have Yuna summon her Aeons and finish him off. This strategy typically also works for other Bosses in the game.
Jay Jarodiya.

Defeating Seymour 3:
In the third fight with Seymour, he is rather tough and uses a combo attack where he uses the Lance of Atrophy which inflicts Zombie on one character then casts Full Life to kill them. He uses this in two turns -- you only have one chance to use Holy Water, which you should have a lot of. Spend some time before the battle running around near the save location just before fighting him. Build up all you characters' and Aeons' Overdrives so that you can use all of them in the fight. It is also a good idea to have at least one character in the fight that has about 3000 HP. Seymour will use attacks that can kill your party in one hit, but 3000 HP should be enough to keep you alive. Have the surviving character use a MegaPhoenix to revive you party then heal it.
jstemple.

Have at least 30 Hi-Potions (preferably more), at least 10 Holy Waters, at least 5 Phoenix Downs and use a party with Tidus, Kimahri, and Auron. Enter the party with Kimahri's Overdrive gauge full. Have Tidus cast Hastega on the party, and do it again if it runs out or Seymour casts Dispel. Keep fighting, using Hi-Potions and Holy Water when needed. When the message "Metamorphos is gaining power" appears, use Kimahri's Overdrive to cast Mighty Guard. After that, just have everyone attack basically, and use a Mega-Potion or some kind of heal all item after each annihilation attack, if you have them. Also, If you guided Kimahri in a certain direction on the sphere grid, he might know "Use". If so, also have him use Al Bhed potions . Seymour should go down quickly, especially if you get Auron's Overdrive full before Seymour casts Protect. Note: Delay Attack/Delay Buster does not work on Seymour.
Skullworm.

You will face his Total Annihilation ability when facing Seymour for the third and final time. To cut this in half, cast Protect and Shell. However, he can cast Dispel. When he does this try to repeat Protect and Shell as fast as you can.
xbosouthiex.

Charge all of yours Aeons' Overdrives and use them. If he has not been killed, cast Reflect on everyone, including Seymour. Then, hit him with all of your strongest moves. He is weak against Fira and Firaga.
FinalFlashX.

Use Bio magic with Lulu to poison him. Every time he uses a move, it will take off 1400 to 2000 HP. Cast Protect and Shell and remember to get your characters' Overdrives full before you fight. Beware of his combo move that casts Zombie followed by Full-Life, which will instantly kill. You should have at least 20 Holy Waters, 50 High Potions, 10 Megapotions, 10 Megaphoenix Downs, and 5 Phoenix Downs. Each of your characters should also have at least 2000 HP and two characters should have 3000 to 5000 HP. A recommended team is Auron, Yuna, and Lulu. You can only use a summons attack one to two times then the Boss uses Banish and gets rid of your Summon. The Boss' weakness is Fire, so use Ifrit when his Overdrive is full. Note: This may not work in the PAL version of the game.
RBondoron.

Seymour is not immune to poison in his first three forms. Use Bio or a weapon with Poisontouch/Poisonstrike to inflict that status on him. Whenever he attacks, he will receive a large amount of damage.
mystifire 414.

Start the battle with everyone in Overdrive (Kimahri, Yuna, and also Rikku recommended). Make sure you have plenty of Holy Waters for Zombie, and about five Ethers. If Kimarhi is in your front line party, have him cast Mighty Guard immediately. Have Tidus cast Hasteaga as well. When he is through, use him to cast Bio or use Rikku's Overdrive to throw a Chaos Grenade. This gives Seymour Silence and Poison. Have Yuna use Ifrit for her Grand Summon to cause good damage at first. Since he cannot cast Dispel because he is silenced, Mighty Guard remains effective for your characters. Yuna is the vital key to victory for this battle. If she stays Hasted and Mighty Guarded, you will have an almost sure victory. The Poison will tick away at him every time he attacks. Attack with a flame sworded Tidus and Auron to move things along. If all this is done, every time Seymour does Total Annihilation, Yuna should be the only one remaining. Have her cast Life, Protect and possibly Reflect if needed on the entire the party. Continue this cycle until he is defeated.
Lawrence Foreman.

When facing Seymour for a third time, it is often best to not fight unless you do the following. Stock 99 Hi-Potions, Potions, Phoenix Downs, , Holy Waters, and Al Bhed Potions (acquired by stealing from the robots around the save point). Each character should be at least 4,000 HP. All characters and Aeons should be at a full Overdrive. Every character should have armor with Zombie Ward on it. You can get this by buying items from the Owaka man; Auron and Yuna are the only characters with it already on their armor. For the rest of the characters, you will have to buy new armor or win them in fights; then buy 30 Holy Waters for each one, and customize it in the customize menu option so that they gain Zombie Ward. Start the battle, and make sure you heal yourself only with a Holy Water if the Lance Of Anthropy is applied and your Zombie Ward did not work.
Jon Davis.

Make sure you have Yojimbo. Have a starting lineup of your best two hitters and Yuna. Start the battle and as soon as it is Yuna's turn, summon Yojimbo. Pay him 4,000 gil and he will kill Seymour with one hit.
dan.

Go there with all your Aeons and Yuna with her Overdrive. Have Yuna, Tidus, and Auron up front. Make Tidus use Haste on Yuna. Then, have her summon all her Aeons and use their Overdrives. If Seymour happens to kill the Aeon and attack a character, it will not matter -- Yuna woll usually go first and you can then summon the rest of her Aeons.
Lakepuke.

Train Bahamut and Shiva until Bahamut's Overdrive does about 25,000 damage, and Shiva has her Overdrive (or any other summon that does 9999 damage). Cast Protect on all characters. Then, have Yuna summon Shiva and then Bahamut to do massive damage. Next, hack away with your strongest physical fighter and LuLu. Have Yuna heal everyone. If Seymour is not dead by the time he does Total Annihilation, make sure you have a person with very high defense. Note: Try to have another Aeon's Overdrive also pumped up. Also, if you have Yuna's Holy, it does a lot of damage.
Nickz2234.

After passing the last save point on the mountain you will engage in one of the toughest battles you have had so far. Start with a party of Yuna, Tidus, and Kihmari. Seymour provides a tough challenge this time. Yuna and Kihmari both have trigger commands. Yuna's Magic Def will rise and Kihmari's Str raises. Tidus should cast Hastega as soon as possible. Have Yuna cast Protect on everyone and have Kihmari and Tidus on the assault. After Yuna has cast Protect on everyone, switch her with Auron and have him use the skill, Mental Break. Then, switch Tidus with Lu Lu and have her cast spells as often as she can. After awhile, Seymour with cast Dispel on everyone, thus disabling your work. On his next turn, he then use Cross Cleave which can deal up to 5,000 HP damage. If Protect is cast on everyone, they will only take half or sometimes, no damage. If you summon, Seymour will cast Banish Of The Damned on your Aeons, thus delivering instant death. This means they only have one turn to attack so they must have a full Overdrive bar. If Mortiorchis charges up for its Total Animation, you should use Rikku's Mix overdrive and have her mix the items required for Mighty G, Super Mighty G, or hyper mighty G. Then, repeat all the steps.
Demon Star.

To prepare for the battle, make sure Yuna has Cura or Curaga and at least 3,000 HP and a good amount of MP. Have some Phoenix Downs. Customize one Yuna's Defense Rings to have Auto-Phoenix on it. Make sure your Aeons and party have Overdrives. Try not to equip elemental weapons for your characters; just use Strength + 5 or something similar. Start the battle with a party consisting of Auron, Yuna, and another strong fighter of your choice (preferably Kimahri, Tidus, or Wakka). Keep Yuna above 2,800 HP in case Seymour uses Cross-Cleave and damages your entire party badly. Put Protect on Yuna. Use Auron and another fighter to hit Mortichois and Seymour. Try to aim for Mortichois more, as he absorbs Seymour's HP when he gets low and he does not really Cure Seymour. If you have Overdrives, use them, except for Yuna's. Do not worry if Auron or other fighter dies because the Auto-Phoenix will automatically revive, and you will not have to waste one of Yuna's turns. If Seymour uses Lance Of Atrophy then Full-Life, which turns someone into a Zombie and KO's them in one shot, use a Phoenix Down on Yuna. Always keep her alive and in good shape (more than 2,800 HP). When you have hit Seymour enough, he will use Get Ready For Annihilation. As long as Yuna is above 2,800 HP, she will revive any KO'd characters. Immediately after Total Annihilation, Summon (or Grand Summon) an Aeon with an Overdrive. Use the Overdrive on Seymour, but he will not be dead. He will Banish your Aeon and they will be dead. When it is Yuna's turn, use Curaga on herself to get ready for a Total Annihilation, which Seymour will probably do. Immediately afterwards, one again do not cure Yuna yet. Summon an Aeon with an Overdrive and use it. You should Overkill Seymour.
InFlames180.

Starting off, you must have at least one character with a least 4,500 HP. If you have two people with 4,500 HP, it helps a lot. Before the battle make sure your all of your characters and Aeons have their Overdrives. Make sure your starting line has your character with 4,500 HP and Yuna. At the beginning of the battle Seymour, will use Lance Of Atrophy which gives Zombie status to a character. He will then kill that character with Full Life. Whenever Yuna gets the chance, summon an Aeon. Use the Aeon's Overdrive. After the attacks of a few Aeons he will cast Protect and Reflect. At this time if you have Lulu, switch someone with her. After you have used almost all of your Aeons, Seymour will use Total Annihilation. He will also sometimes use Flare immediately afterwards. After Total Annihilation, Reborn and heal all characters. By the time you have used all the Aeons and Overdrives, he will be very close to be defeated.

Defeating Seymour 4:
Do not attack the Elemental Wheels. Use the opposite magic that he turns to with Lulu. When he turns to non-elemental, hit him with your Aeons' Overdrives. He will use Ultima to kill your Aeons, but he will get hurt only when he is on gray.
FinalFlashX.

Blue: Water
Purple: Blizzard
Red: Fire
Yellow: Thunder
Gray: Non: elemental

Get Anima and train him until his HP is higher than 5,000. Get Tidus' Overdrive. His strength must be on 50 or higher. Immediately after the battle, equip a the Brotherhood Sword. Once you begin use Tidus' Overdrive, he should get between 2,500 and 3,000 damage. Summon Anima and use his overdrive. If needed, finish him with your strongest character.
Mtadog246.

Get Anima and get it into overdrive. Also get Auron into Overdrive. Use Auron's Overdrive first and use Banishing Blade. This will make it more vulnerable to physical and magical attacks. Then, summon Anima and use its Overdrive Oblivion. Each punch will do about 10,000 damage.
Adam Wright.

To make this battle extremely easy, have Tidus's legendary weapon, the Caladbolg. Once it has achieved its maximum power, Tidus will be able to damage an enemy for 20,000 to 24,000 HP. Make sure Yuna knows the four Nul Spells, as they will be very handy to protect against Seymour's strong magic. Start with Tidus, Yuna, and Auron. Get to Yuna's turn and cast a Nul Blaze immediately to nullify Seymour's Quad-Firaga. With Tidus "hopefully" being hit twice, his Caladbolg will allow him to counter Seymour's attacks for 50,000 damage total. The trick here is to have armor that eats fire, so when Tidus gets hit the first time, he nullifies the fire. The second time he is hit "hopefully", he will convert the fire into HP for him. Then, finish Seymour off with some slashes of Auron's sword. If you really want to win easily, have the Aeon Anima and its Overdrive, Oblivion. Seymour will definitely go down after this horrific Overdrive in one turn.
Ztegge.

After you defeat Sin's head, you will come across a strange place. Enemies will pop up. Fight them with Ifrit, Ixion or Shiva. By the end of the path there should be stairs. Make sure Ifrit, Ixion, and Shiva are in Overdrive. Start with Yuna, Lulu and Auron. It usually starts on the element fire (red). Call upon Shiva and use her Overdrive, because fire's weakness is ice. It should do about 50,000 damage. He will use Ultima to kill Shiva and maybe a few Firagas. Come back to your playing characters and Seymour will use Dispel. It will all miss. If Yuna is still out, switch her with Tidus and make him use Hastaga on Auron, Lulu, and himself . When Lulu attacks, use Doublecast Bizzaga (fire). He should not have changed the elements yet. Keep using it. On Auron's first turn, use Armor Break because Seymour has a high defense. Tidus should be up next. Switch him with Kimahri or whoever has a higher attack power and make them attack. Keep using Lulu's doublecast and Auron's and Kimahri's attack. He should be dead after a few more hits. Remember, if HP runs low. use Mega-Potions and have about two Mega-Phoenix. You do not need any hidden Aeons in this battle.
catgirl.

Have Wakka in your party and make sure you have his "Attack Reels" Overdrive. Before entering the battle, get Wakka's Overdrive up. During the battle, cast Attack Reels, and get all three two-hit slots lined up for a one hit battle. If each hit does at least 7,000 damage he will die on just that Overdrive. Also, whatever element that he has chosen, have Yuna summon the Aeon of that same element. Whenever he casts the spell of that particular element, the Aeon will absorb it. Note: Seymour will eventually banish your Aeon.
Jason Tatro.

Start with Rikku, Tidus and Wakka. Make sure Rikku and Tidus have their Overdrives full going into the battle. Start the battle and make sure Rikku goes immediately before Tidus. Use Rikku's Overdrive Trio of 9999 by using either two Doors To Tomorrow (stolen from the Ultima Weapon) or two Gamblers Spirits (stolen from the Omega Weapon). Then, have Tidus use his Overdrive Blitzace. The first eight hits will each take 9999 (79992 total). If you do not make the last move, which would have overkilled him, just attack with Wakka or whoever else you want to defeat him with.
carparelli.

Make sure that you have about five to six Dark Matters. These will do 60,000 to 70,000 damage together. Then, summon Bahamut and use his Overdrive.
Stefan Jørgensen.

Make sure you have Anima and Ifrit with their Overdrives. The order for the element wheels on the sides, above, and below Seymour is as follows: fire, ice, water, lightning. When the fire one is up, summon Shiva and use the Overdrive. if you have the ultimate weapon that allows Shiva to break her damage limit and if Shiva's status is high enough, it should do close to 50,000 damage. Seymour will then use his Firaga nearly ten times. Shiva will most likely be dead at that point. Next, Seymour will probably start to glow, indicating he will use Ultima. Summon Ifrit when he starts to glow. If Ifrit's HP is high enough, it should survive this devastating blast. Seymour's, wheels will then spin to match up to ice. Use Ifrit's Overdrive. If you have Ifrit's status high enough, and if you have Auron's ultimate weapon, he should do about 70,000 damage and defeat him.
sbrowne.

Defeating Shinryu:
To defeat Shinryu in the monster arena within three turns, you must have Tidus, Rikku and Wakka in your formation. They should also have their Celestial Weapons fully activated. Their strength should be sufficient to inflict 99,999 damage on a normal enemy and most Bosses with each hit. You should also make sure that Tidus has learned the Blitz Ace Overdrive and Wakka has learned the Attack Reels Overdrive. Make sure that all three have full Overdrive gauges. If Rikku is the first to go, then use her Mix Overdrive and mix a Bomb Fragment, Electro Marble, Fish Scale or Antarctic Wind with a Luck Sphere or a Designer Wallet to make the Miracle Drink. This allows all hits to become critical. Then, if Tidus is next in line, have him do his Blitz Ace attack to inflict 9 x 99999 damage. At this point, Shinryu will counter-attack but you should have enough health to hang around. Then, have Wakka do a perfect Attack Reels to inflict about 12 x 99999 damage. This is the quickest way to defeat Shinryu.
Jaded.

Defeating Sin:
Get the secret Aeon Anima, and get it into Overdrive. Next, get Yuna in Overdrive. Then, get Rikku and Kimahri in Overdrive. Fight Sin and before he pulls you in, get Tidus and use Hastega. When Sin pulls you in, use Rikku to throw a maximum amount of Gil. It will do 9,999 damage to Sin. Then, use Kimahri's Overdrive and use Thrust Kick. If you have Nova for Kimahri's Overdrive, use it instead because it does a lot of damage (either 6,200 or 9,999). Then, use Rikku's Overdrive. Combine two ThreeStars (which can be acquired at Calm Lands for catching certain enemies in a certain region). After you combine them, it will do Sunburst which does 12,000 damage. Bring out Anima and use its overdrive. After its Overdrive, dismiss Anima and use Yuna's Overdrive on Anima. Then, use anima's overdrive again. It will do about 80,000 damage after using Animas Overdrive twice. Dismiss Anima, switch Yuna with Tidus, and switch Rikku with Auron. Your party should now consist of Tidus, Auron, and Kimahri. Use Tidus to cast Hastega on the party. Have Auron use Armor Break and have Kimahri to use Zombie Break. It does not inflict Zombie on Sin, but does do a lot of damage.
Mooncodan.

It is possible to defeat the very last Boss without the use of any of the special weapons, damage limit break, or health limit break. Once the battle starts, cast Magic Break on him. This will lower the amount of HP he can recover after each hit he takes. Depending on how much you have built up your magic ability, you can lower his health regain rate by up to 50%. If you then keep a constant rate of attack on him, you can defeat him. However, depending on your characters strength, this may still take some time.
SerratedEdge4.

Get Anima and the Magus Sisters. Their Overdrives should do over 18,000 damage. Another way is to get the Legendary weapons and use all the Aeon's Overdrives. They will all do over 9999 damage if you have all of them.
dsmer.

Have a party consisting only of Rikku, Tidus, and Yuna. Rikku needs to have Holy and 1 MP spells in a slot in her weapons abilities. Only Tidus and Yuna should have the Auto-Med ability. Rikku and Yuna must both know the Holy spell, and Yuna should know Ultima. Have the Piercing ability equipped to Tidus' wepon. At the start of battle, have Tidus cast Hastega. Since Rikku has the 1 MP ability, have her start casting Holy non-stop. Tidus should keep attacking, using the "quick hit" ability and Yuna should randomly cast either Holy and Ultima. Since she should have high MP, do not worry about her running out of MP. When Sin gets close enough, have Rikku keep using Steal until she gets the Supreme Gem. This item casts Ultima on all enemies once. However, do not use it in this battle. Yuna should heal Hp with Cura, Curaga, Hi-Potions, X-Potions, Mega-Potions, or Elixirs, but keep Tidus and Rikku doing damage.
DemonStar.

Before you go into battle, make sure you have Lulu and Yuna with Ultima in their Black Magic List and "One MP Cost" added to their weapons, since they would have more strength to their magic than any of the other characters. This will work just as well on Sin Left Wing, Sin Right Wing, Sinspawn Genais, and the weak spot behind him. After you defeat Sin Parts, you will fight Sin face to face. Continue to cast Ultima on Sin until his Overdrive Meter is about 85% full. By then Yuna should have her Overdrive meter full. Use Grand Summon on Bahamut to finish off Sin.
Collin Beishir.

To defeat Sin, use Anima's overdrive. Dismiss her, then summon the Magus Sisters. Use their Overdrive. If Sin is not defeated by then, summon Anima to finish him off.
tam.

Defeating Sinspawn Gui:
Destroy the head first, so he does not do much damage. Next, destroy both his arms. Have Auron and Wakka in your party. Auron can destroy the arms and Wakka can destroy the head. The head just has 1000 HP and the arms have 800 HP. Do not change Auron because the arms will regenerate. When you fight Sinspawn Gui 2, you will have Seymour in your party. Have Seymour use Thundara on the head. Next, have Yuna summon an Aeon with its Overdrive (if available). If not, just do the same thing as last time without Wakka in your party. Also, use Seymour's Thundara ability on the body, which has 6000 HP, to destroy Sinspawn Gui 2 faster. Remember to take out the arms first.
WDelpo and Martin Bradley.

Have Lulu use Fira (recommended) or Fire on the head. Once the head is taken out, have Lulu use Fira on the body and Tidus use Cheer to increase the attack of your party members.
Hottluvrboy95.

Defeating the Spectral Keeper:
Have your Overdrives full and use them. You should have between 4,000 to 6,000 HP, Aga magic, lots of curing items, and Protect (to muffle the power of the Boss' moves). He does a move called Glyph Mine that kills you instantly. Getting hit by this is pure luck. He normally only does it one to two times.
RBondoron.

Make sure all your Aeons' Overdrives are powered up before the fight. Have Tidus, Yuna, and Auron in your party. Have Tidus cast Haste on Yuna, then have Yuna summon her Aeons as quickly as she can. After each Aeon uses their Overdrive, the Spectral Keeper will probably use Glyph Mine on it, killing it instantly. If not, just have it keep hacking away at it as much as it can, healing itself when necessary. You can keep Tidus and Auron in there to heal Yuna, or you can swap them out for other characters to get them some experience.
BTgamer.

Defeating the Spherimorph:
To prepare, start training vigorously from the time the game starts to the time you get to the Spherimorph (about ten fights minimum in each area). You should have about 15000 gil or more when you are ready. Go to O'aka and ask for weapons. Leave, then he will ask you about the prices. Tell him that they are too expensive, then go back and buy weapons. The prices should be lowered to some extent. Buy the Sonic Steel for Tidus, Rod of Darkness for Yuna, and the Force Knuckles for Rikku. When you get to the part of the Macalania Woods where you fight Spherimorph, immediately save if you are uncertain that you can defeat it. To fight Spherimorph you should equip the following recommended items. Tidus (Sonic Steel, any armor with Magic Def 3or 5%), Yuna (Rod of Darkness or Laevatein, Seeker's Ring; HP + 10%), Wakka (Switch Hitter, Emerald Armguard), Lulu (Fatal Cait Sith or Water Moomba, Seekers Bangle), Auron (Shimmering Blade, Recovery Bracer), Rikku (Force Knuckles, NulBlaze Target), Kimahri (Hunters Spear, Red Armlet). Start the fight with Tidus, Auron and Wakka. Tidus goes first, so set the tone with his Overdrive (if he has it). Do not use Wakka's Overdrive because it is elemental and will heal Spherimorph. Instead, use a physical attack. Use Auron's Magic Break to weaken spells, then switch in Kimahri and use his Jump or Seed Cannon Overdrives (if he has them). Use Yuna and summon Ifrit. Use his physical attacks to damage Spherimorph. Spherimorph will attack with Fire, thus healing Ifrit. Switch out Ifrit and use normal characters occasionally. Switch Ifrit back in and use his physical attacks until Spherimorph starts using its physical attacks frequently. Dismiss Ifrit and use Auron's Power Break to weaken its physical attacks. Then, finally pummel it down with either Ixion or Ifrit's physical attacks, occasionally healing them with elemental spells.
Richard Tucker.

Have Tidus, Lulu, and Yuna on your team. Use Yuna to cast the Nul spells, then use Tidus' attack. Spherimorph will cast an elemental spell on Tidus. However, if you used the Nul spells it will not harm him. Have Lulu cast the opposite of that spell/ Spherimorph will then use Elemental Shift. Keep repeating this and Spherimorph will soon be dead and you will suffer no damage.
Da D Man.

First, equip your heavy hitters with weapons that are non-elemental to prevent Spherimorph from getting healed. Start out with Rikku, Lulu and Tidus. Rikku should be the first one up normally. Change her for Auron, who should attack with Magic-Break. Spherimorph will retaliate with his spell Counter, so you can easily tell its element. Haste Auron with Tidus , add a Power Break for good measure, and slice away with Auron and Tidus using the warrior mode to get your Overdrives up). Do not use Auron's Overdrive, as it is elemental in nature. Use Rikku's Overdrive to heal your party with two Potions or switch Lulu for Yuna to heal your party. You can use Lulu's Focus ability to guard from the spells and Tidus' Cheer ability to protect from his basic attacks. When you estimate the Boss has dropped to about 2,000 HP and has changed to Ice element, get Yuna in to grand summon Ifrit so you can overkill easily for extra AP.
Mikal Boesmans.

Start with Lulu, Yuna, and Tidus in your party. Have Tidus hit the Spherimorph with a non-elemental attack to reveal which element it is currently using. Then, have Lulu cast the opposite spell to force it to use Elemental Shift. Repeat this process, using Yuna to heal in between attacks, until a Thunder spell is cast. Then, use Yuna to summon Ixion. Use his generic "Attack" command and this will force Spherimorph to use a Thunder spell, which will heal Ixion Repeat this process until Spherimorph is dead.
Gary Sarbacher.

Use Yuna's second Aeon. When Spherimorph uses a fire attack, it well give him life. Then, attack him. If he uses any attack that takes away HP from your Aeon, then use fire on the Aeon. You will eventually defeat him.
Lakepuke.

Summon Ixion and attack. Every turn, Spherimorph will cast Lightning. Then, either use Press or just attack. The lightning will heal you, then Spherimorph will hurt and you will never die.
MewR91.

Have Lulu, Yuna, and Rikku on your team. Have Rikku attack to find out which element it is using. Then, have Lulu cast the opposite of what it is using (fire, use ice; water, use thunder; ice, use fire; thunder, use water). When your party's HP gets low, have Yuna heal your team. When Rikku's Overdrive is full, use Mix. Mix a Map and a Lunar Curtain. This will make a Mega Nulall. When it uses a spell, your team will not get hurt. Have Lulu cast spell to defeat it.
LWayne2005.

Defeating the Stratoavis in the Battle Arena:
Once you collect all the monsters from the desert, go back to the Calm Lands and go to the Battle Arena. If you have caught all of them, the man will offer you a free fight with the new monster he just created. Accept his offer. Once in the battle, make sure you have Yuna in your party. Wakka and Tidus are also recommended. To make this faster you will need the Aeon Yojimbo. He can dodge all the attacks from Strutoavis and put Yojimbo in Overdrive. This should enable you to pay a low price for maximum damage. You should be able to pay 10 to 20 gil and he will do one of four attacks. If he does Wakizashi or Kozuka, it should do maximum damage. Do this about fifteen to twenty times and he should fall. You should get about 10,000 AP for winning, and perhaps a Key Sphere.
Derrick Gage.

Defeating Tonberries:
Put them to sleep.
Gary Hodson.

If you cannot get the items to customize the AP Weapons (Triple AP, Triple Overdrive and Overdrive -> AP), it is possible to win them from Ultima Buster. It is very rare, however it does happen. To easily defeat Ultima Buster, use Anima. Cast Protect and Haste, and attack the head until it dies. Use magic on the body, and when you get Overdrive, use it. It will destroy the arms. Then launch a flurry of attacks on the body. It takes a lot longer in the North American version of the game to win this way than it does in the PAL/International version. Oblivion hits for up to 1,599,984 damage in the PAL/International version, but only up to 99,999 in the North American version.
Steaver370.

Defeating Ultima Weapon:
You can bribe Ultima weapon for 1,200,000 gil. He will give you a lot of the rarest item in the game.
Yvl9921.

Defeating Warrior Monks:
To defeat Warrior Monks in one shot at Bevelle, switch to Lulu and use Thundaga. For the machines, use Wakka's Dark Attack.
BDExperement11.

Defeating Yu Yevon:
Use the Zombie Attack on Yu Yevon. After every attack, he will cast Curaga on himself and take extra damage because of his Zombie status.
Jeffrey Smith.

Use the Zombie Attack on Yu Yevon. If it hits, the next time it is your turn use a Phoenix Down on him for an instant kill.
MajinKiller9031.

When fighting Yu Yevon, use Reflect or Star Curtain on some of your party members. Although you automatically have Auto-Life, it is a good idea to keep all of your members' health up. The higher your health, the more damage inflicted to Yu Yevon. Another good tactic is to get Tidus' Overdrive up and use Slice And Dice on Yu Yevon.
Game Mage.

Press Triangle through the entire battle and eventually he will kill himself with his own moves. Iif you do not attack him he will not use Curaga, and if you die you will automatically return to life.
eddy morris.

In the Zanarkand Dome, you can Steal from fiends the Candle Of Life. Try to steal from every fiend you encounter in the Zanarkand Dome and you should find it. After disposing of Lady Yunalesca, Sin, Seymour and Jeckt, you will encounter Yu Yevon. When the battle begins, bring in Rikku and use the Candle Of Life and a number should appear on top of his head, counting down to his death.
Goodguy4yall.

Use Lulu to inflict Death. If Lulu has not yet learned Death, then charge Kimari's Overdrive in the battle with the Aeons.
FinalFntasy10.

Have Lulu and Yuna use Ultima repeatedly. Note: If you leveled up Yuna and have her Nirvana, she should do about 50,000 damage each turn.
SailorGMoon.

Have the Celestial Weapon for any character. The character's Strength must be over 200. One attack which causes 99,999 damage will kill him.
Edric Solis.

Get Overdrives with Rikku and Lulu. Use Mix with two Wings Of Discovery or, if not that, Wings Of Discovery and a Door To Tomorrow. This will make a Trio Of 9999. Use Lulu's Overdrive and get 11 to 14 Drains by rotating the Right Analog-stick very fast. He should be defeated in two moves.
Lynd.

To defeat Yu Yevon very quickly cast Doom on him. This will kill him in three turns.
Richard Sulston.

Get Yuna or anyone with Reflect to cast it on Yu Yevon. Attack only him and do not use Black magic. When he uses Curaga after every hit, one of your characters will get healed for 9,999 HP.
Mike D'Angelo.

Use the spell "Boomerang" on Yu Yevon. When he heals himself, it will heals you. Then, take Auron, Tidus, and Kimahri. You should be able to defeat him even with Rikku. Use a spell that can inflict the Zombie status to the Boss. Then use the spell that revives someone.
RoXaZ.

Defeating Yunalesca:
Yunalesca has three stages. Her first form is quite simple. Just use physical attacks and magic. Do not use Overdrives or Aeons. Her attacks are very weak and she is killed easily. Her second form is a more difficult. She does an attack which casts Zombie -- have plenty of Holy Waters available. In this part, use your players' Overdrives, but no Aeons. Yunalesca's third form is not very difficult. Just have your Aeons' Overdrives ready and finish her off with a couple of physical attacks.
FF Master.

Yunalesca has 164,000 HP when you add up all three parts. You should have at least 4,000 to 9,999 HP on most characters. First, just attack and use magic. Ultima woks well if you have it. After you kill its first form, a more difficult form appears. On this form, simply attack and use some magic but do not use summons. The final form will cast Death, but it can be counteracted with Zombie. However, if Zombie is on it will cast curing magic and regain. You should have 99 Hi-Potions and Phoenix Downs; and a good supply of Ethers and Mega-Potions. Some Elixirs and X-Potions are also good.
RBondoron.

Her first form is easy. Just use physical attacks and some magic. In her second form, she does Hellbiter which requires Holy Water as a cure. Have at least fifty and some Phoenix Downs, Her third form is quite . Just use your Aeons' Overdrives (if available), or yours. If she is not defeated, use more magic.
armygal619.

On her third form, try to keep at least one character in Zombie status. This will prevent them from dying when Yunalesca casts Mega Death. Hack at her with physical and magical attacks (such as Holy) on her first two forms. On the third forum, use Aeons'/characters' Overdrives.
Adam Schepman.

When Yunalesca is in her first form, just use attacks and magic. With the second form, do the same thing only Heal when you get hit with Hellbiter; or use Auto-Med if available. When she is down to 5000 hit points, summon Valefor and use his Overdrive. When the third form Megadeath attack appears, it will not hit your party members but hit your Aeon instead. Then, just finish her with Holy and other Aeon overdrives.
SailorGMoon.

Get the Celestial Mirror and Yuna and Kimari's legendary weapons. After Seymour 3, get Kimari's Crest then capture all the monsters in the Calm Lands to get yuna's weapon. Get her Crest on Besaid Beach. Then, power up her weapon halfway with the Crest. Do the same for Kimari. Valfor, Bahamut, and Ixion should now be able to do about 23,000 to 24,000 damage. Get all their Overdrives up, including Wakka's Attack Reels. Start by using his Attack Reels, then use a Aeon such as Shiva that can only do 9999 damage. After the first form, cast Haste on Yuna with Tidus. On the second form, use Bahamut and keep healing him with cure magic if you have it. You should get at least two overdrives from him if you keep healing. After the second form, use the last Aeons to your advantage and kill her. If done correctly, your characters should not have been harmed and you should still have other Aeon Overdrives to burn.
Joe Stottlemyre.

Have Yuna use Holy on all of her three forms. Also, have Rikku's overdrive Mix available. With Rikku, mix Musk and Ether to create Freedom X, where there is no MP cost. Then, if desired, have Rikku use Light and Lunar Curtains to cast Protect or Shell on your party. You should have no problem with Yunalesca's first form, but when she uses Hellbiter in her second form keep someone who has Hastega in your party in the Zombie status. When she shows her third form, have that person who has Hastega revive them with a Mega Pheonix. It is possible to defeat Yunalesca in about three minutes. Note: Auron should have Holy, Flare, Doublecast, and Ultima.
Nate.

Make sure you have armor that protects against Death, Zombie, Darkness, Silence, and Sleep. Her first form is easy. Attack her until she dies. Be careful; each physical attack is met with Blind, and each magical attack is met with Silence. Yunalesca even counters specials such as Steal, with Sleep. After transforming, she will start to cast Hellbiter. Hellbiter inflicts Zombie on characters. Leave some characters in Zombie status for her third form. Yunalesca will cast Regen on your characters in Zombie. If you use a Holy Water or Remedy fast enough, it will heal instead of hurt you. Make sure that Haste is in effect on the entire party at all times. When she can be killed in one attack, bring in the character in Zombie status to do it. When Yunalesca transforms into her third form, she will immediately cast Mega Death. If your party is in Zombie status, it will not affect them. If someone in Zombie status is hit with Regen, have Yuna cast Dispel on them. Then, bring in your strongest Aeons and perform their Overdrives (usually, Bahumat, Shiva, and Ixion). Once Yunalesca is dead, walk around outside of the dome until Cid appears with the Airship. Afterwards, the Airship is yours. You may now want to finish any mini-games you missed and get the rest of the Aeons.
Michael Lyons.

Yunalesca has three forms. He first form is quite simple. First, make sure Yuna knows Reflect and that Yuna and Tidus both know Steal/use. Then, put Tidus, Auron, and Yuna out. Make sure their overdrives Are full. First get Tidus to use Hastega. Then, get Yuna to cast Reflect in the following order: Yuna, Auron, Tidus. Next, have Kimarhi's Overdrive full but make sure he has the ability (learned from using Lancet on The Ronso Brothers) Mighty Guard. Swap Auron for Kimari and use Mighty Guard. Then, swap Auron back. Next, have Yuna cast Reflect off Yunalesca. Continue to whack at her first form with your normal weapons while Tidus and Yuna heal with Al Bhed potions. For her second form, let her use Hellbiter until at least one character is zombiefied, but make sure that there is at least one character that is not. Allow Yuna to summon all of her Aeons in Overdrave and use their Overdrives. Her second form should be easy. For the third form, beware of her "Mega-Death" attack. It will kill all characters that do not have Deathward, Auto-Life, or Zombie status. Continue to hit her with your Aeon's and character's Overdrives. It should be an easy battle.
grimreaper666.

Have your Aeon's Overdrives ready. Give two out of the three characters in your starting line Zombie-proof armor. Make sure that at all times, especially in her second and third forms, that one person has Zombie. She will start by countering your attacks: Attack - Blind, Magic - Silence, and Items - Sleep. She will also use Absorb and attack. Do not use your Aeons on her first form. Her second form is more difficult. She will start using Hellbiter. This will do damage and give Zombie status. She will also use Regen on one of your characters that has Zombie, doing damage. During this form keep Yuna out, but try not to use your Aeons. You will need them for her third form. During her third form she will use Mega Death which will kill all of your party. If you have a person with Zombie they will not be affected by Mega Death -- have at least one character with it during the third form. Use the rest of the Aeons. If you use some on the second form and if you have learned Holy, now is the time to use it.
TommyDoyle.

Defeating Bosses:
Get all your Aeons' Overdrives character's Overdrives up before battle. When you enter the battle, let everyone hit once with their Overdrive (so at the end they all get experience) and let Yuna summon her Aeons and use their Overdrives. Try using Yuna's Overdrive "Grand Summon" and summon your best Aeon. You can use two Overdrives with hem if you charged them up.
Rusty616.

To defeat almost any Boss in the game, go through the Monster Arena side quest until the man gives you 60 (99?) Gambler's Spirits. Next, build up your characters' Overdrives. With a party that includes Tidus, Rikku, and Yuna, go into a battle. Usually Rikku will go first -- have her use Overdrive: Mix and combine two Gambler's Spirits. This casts Trio of 9999 (makes the next time the character attacks to do 9999 damage). Then, use Tidus and his second Overdrive. Since you cast Trio of 9999, all six of Tidus' attacks will do 9999 damage for a grand total of 59,994. Next, have Yuna Grand Summon a strong Aeon (Anema, Magus Sisters, Bahamut) and they should do about 30,000 damage for a grand total about 90,000. This should kill any Boss except for Omega Weapon, and the second form of Braska's final Aeon. For even more damage, make sure all of your Aeons are also at Overdrive.
Dusty Thell.

Get Anima, Yojimbo, and The Magus Sisters. Train with them a little while and when you encounter a Boss, the battle will be easier. To make a Boss fight even more easy, get all your Aeons, including the secret ones, and get them into Overdrive.
Mooncodan.

Have Rikku and Tidus in Overdrive and equip them with their legendary weapon. Have Rikku use her Overdrive Mix to combine two Gambler's Spirits. Do this immediately before Tidus' turn. On Tidus' turn, have him use his Overdrive Blitz Ace. The first seven hits will all do 9999 damage and the last hit should do at lest 15,000 damage. This winds up doing more than 80,000 damage to any Boss. However, this will not kill Braska's Final Aeon second form and Sin's head.
Coro175.

When attacking a Boss have Yojimbo's overdrive full. Pay him gil so he does his special attack. This attack seems to do no damage but it kills it instantly. This attack is rather random -- it is possible to do the attack Zanmato without having an overdrive. It just increases the chance that it happens. You have to pay Yojimbo the correct amount. Paying him massive amounts will not always work. For example, it may work when 1111 gil is paid.
Jonathan Willis.

Make sure you have at least two Doors To Tomorrow. Tidus must have Blitz Ace. Rikku and Tidus must have Overdrive before the battle. When the battle begins, have Tidus cast Hastega then have Rikku use Mix and use two Doors To Tomorrow. This causes Trio of 9999, which makes all of your attacks do 9999 damage. Next, have Tidus use Blitz Ace. Every hit does 9999 damage, and for Blitz Ace this results in exactly 89,991 damage. You do not have to worry about getting the correct timing on the final hit -- it will always do 9999 damage. This is enough damage to kill Omega Weapon in one attack. This technique also works for Wakka's Aurochs or Attack Reels, although the damage is different.
mthrasher01.

To defeat Bosses easily, you need three essential things. They are x2 Gambler's Spirit (or x2 Door To Tomorrow), Tidus' Overdrive Blitz Ace, and Wakka's Overdrive Attack Reels. When starting the battle, make sure that you have Rikku, Tidus, and Wakka out, all with Overdrives. Rikku should go first. Use her Mix Overdrive and combine the x2 Gambler's Spirit (or x2 Door To Tomorrow). It should make Trio Of 9999 which makes any attack automatically hit for 9,999. Tidus should be next. Use his Blitz Ace Overdrive . If done correctly, you should have done nine hits of 9,999 on the Boss (about 89,991 damage). Wakka will be next. Use his Attack Reels Overdrive . If you lined up all three 2 Hits, he should do about twenty hits of 9,999 to the Boss (about 199,980 damage). The total damage done to the Boss should be about 289,971. This amount of damage, if done correctly, will kill any Boss except the Arena creations. If you are fighting an Arena creation, and have not killed it yet, you can switch out the next person (Rikku most likely) with a character that knows Entrust and has an Overdrive. Use Entrust on Wakka and do Attack Reels correctly again for another 199,980 damage equal to a grand total of 489,951. This will kill almost all the Arena creations except the originals and Nemesis. Note: This can be used even against underwater Bosses. If you want even more damage, keep switching out with characters that know Entrust and keep using it on Wakka.
Andrew Meza.

Defeating Machinas:
Use the following trick to defeat any Machina (except for the Bosses). Use Tidus' and Rikku's Steal ability on it and they will just crumble.
Footballstud5684.

Defeating Dark Aeons:
Use Yojimbo, and give him large amounts of money until he does Z