Seymour Omnis The final battle with Seymour Guado , the battle against Seymour Omnis , is staged inside Sin . Seymour ' s plan is to gain control of Sin from the inside to wreak havoc on Spira , his pyreflies having been absorbed by Sin . Defeating Seymour Omnis in the " Final Fantasy X HD Remaster " version earns the The Destination of Hatred trophy . Battle . Seymour Omnis hovers in front of four discs called Mortiphasm s . On his turn he will cast four spells in succession on the player party . The spells are determined by the color of the discs closest to Seymour : orange for fire - elemental , purple for ice - elemental , yellow for lightning - elemental and blue for water - elemental . The spells ' strength is also determined by how many discs of the same color are closest to Seymour . For example , if only one orange disc is aligned , Seymour casts a weak Fira spell , whereas four orange discs allow Seymour to cast four powerful Firaga spells . The Mortiphasms govern Seymour Omnis ' s elemental attributes : Once Seymour Omnis is attacked six times he will glow red , indicating his change of strategy . He will cast Dispel on the party , and on his next turn cast Ultima that can potentially exceed 4 , 000 damage to the party . He will rotate the Mortiphasms so that the aligned discs match ( but of a different element than before ) , and continues with his previous strategy . Once Seymour Omnis falls below 20 , 000 HP , he will do this after only three attacks ; counterattacks also count towards this . If his spells are blocked by Nul - spells ( and not by immunity or absorption ) , it is possible to counterattack them . This can lead to multiple counterattacks to a single one of Seymour Omnis ' s turns ; this is the only case in " Final Fantasy X " where this can happen ( the Nul - spells are not a requirement for this to occur ; if one simply takes damage it can also happen ) . Seymour will no longer banish aeons like he did in the previous two encounters , and remarks that even his mother opposes him if Yuna summons Anima . Although Seymour Omnis ' s defense is initially 180 , it is reduced to 100 whenever he casts Dispel . When he uses Ultima , it is increased again , but only to 150 . Seymour Omnis ' s version of Ultima is different from most Ultima spells in " Final Fantasy X " . It is somewhat weaker , having a damage constant of 64 instead of 70 ; the damage is only about 89 . 4 % of what a normal Ultima spell at 35 magic would be . This is somewhat made up for by Seymour Omnis ' s Ultima dealing special damage rather than magical damage rendering most protective measures useless . It can still be reduced by Shield and / or Focus . There is a minor glitch : When Omnis has two water elementals , he becomes immune to Fire rather than to Water . This can even lead to a situation where Omnis is both resistant and immune to fire . This persists across all versions of the game . Strategy . As the discs face the same way at the beginning of the battle , one of the first actions should be to rotate one by attacking it to prevent a barrage of powerful spells . Physically attacking a Mortiphasm will rotate it counter - clockwise , and using magic will rotate it clockwise . The Mortiphasms , unlike Seymour , are out of range of melee attacks , so only Wakka can attack them physically . Seymour Omnis has high defense and magic defense , so using Armor Break and Mental Break will make the battle easier . Holy and Doublecasting elemental spells that target Seymour ' s weakness are also effective , although the latter will only work if the player doesn ' t attack the Mortiphasms . Casting Hastega or using items or Mixes that grant Haste to the party are useful , however , Seymour may Dispel this , so the player would need to reapply . The player can let Yuna ' s aeons do the work : unless Seymour is using Water spells , it is possible to just summon the corresponding elemental aeon who will absorb the spells . Another useful tip is to have Yuna ' s Overdrive full before the fight and summon Shiva and use her Overdrive without Lulu ' s Venus Crest ( found during a second visit to the Farplane ) she will do 9 , 999 damage if Yuna is trained , or with the Venus Crest on Lulu ' s Celestial Weapon , she can do anywhere from 0 - 99 , 999 damage effectively one - hit KO ' ing Seymour . As Seymour primarily uses elemental magic to attack , it is recommended to equip armor that nullifies or absorbs his spells : the Phantom Bangle for Lulu can be found on the Battle Site , the Phantom Ring for Yuna is found in the Sea of Sorrow , and the Victorious for Rikku is found by inputting the password " VICTORIOUS " on the " Fahrenheit " . Using Nul - spells is a viable alternative , but this leaves the party open to Seymour ' s fourth spell . Another strategy is to use weapons with all four elemental strikes and armor with all four elemental eaters . For example : If Tidus attacks with the Crystal Sword it will do 1 . 5x damage when the discs rotate for a certain element , and even if Seymour changes for another element , this will happen due to Seymour always being weak to one element when he changes the discs , and with Crystal Shield , most of Seymour ' s spells will heal Tidus except for Ultima . This strategy with more two more party members will render the player nearly invincible . Etymology . Seymour Omnis is called " Seymour éthéré " ( Ethereal Seymour ) in the French version , " Seymour Omega " in the Spanish and Italian versions , and " Seymor Ultima " in the German version .