Seymour Flux The third battle with Seymour , in his Seymour Flux form , occurs after Yuna and her guardians make their way up Mt . Gagazet . The battle is notorious for being among the hardest non - optional boss es in the game due to Seymour ' s powerful attacks and his signature attack , Total Annihilation . Battle . Seymour summons Mortiorchis , upon which he sits . As with previous Seymour battles , certain party members may use the Trigger Command to talk to him . For this battle , Kimahri can talk to Seymour to raise his Strength , and Yuna can talk to him to raise her Magic Defense . Seymour Flux can use the attack Lance of Atrophy to put an ally into Zombie status , and the Mortiorchis will combo with Full - Life , effectively KO ' ing a character ( unless the characters have high Agility , as well as Holy Waters ) . Like Seymour Natus , he can Banish aeons , giving it approximately one turn to attack if summoned . Seymour Flux occasionally casts Protect and Reflect upon himself . Three turns in , Mortiorchis will start to use Cross Cleave , which deals around 2 , 000 damage to the whole party . Seymour will then cast Reflect on himself and rebound Flare at a party member , but a character with high Agility or in Haste may get a turn in between and can Dispel Seymour , causing him to cast the spell on himself . Total Annihilation is Seymour Flux ' s signature attack , as well as his deadliest , which requires three rounds of charging , and will kill anything but an extremely good party . If the player summons an aeon Mortiorchis will postpone its use of Total Annihilation until Seymour Flux banishes it . Seymour is immune to Breaks , and has greater Magic Defense and physical Defense than the average enemy . Magic , such as the White Magic Holy , or the Black Magic Flare , should still do considerable damage , due to their high base values . Characters with high Strength or Magic will still do decent damage , no matter the type of attack . Since the Piercing ability can penetrate Seymour Flux ' s Defense , Piercing physical attacks will do relatively more damage than magical or regular physical attacks . Seymour Flux is vulnerable to the Poison status ( the Mortiorchis is immune ) and will take 1 , 400 damage at the end of his turn ( sometimes , he will get two turns in a row not long before Mortiorchis , so he ' ll use Lance of Atrophy on his first turn then skip the second , thus he will react to damage twice just a second apart ) . Strategy . One way to inflict damage as well as Poison is to use Rikku ' s Mix and combine a Fire Gem and Soul Spring . To protect the party from Seymour ' s Lance of Atrophy , the player can either equip them with Blessed armor ( can be bought from Wantz on the mountain , or made by customizing a piece of armor with Holy Water ) , or use Holy Water on the afflicted character before Mortiorchis can cast Full - Life . Armor customized to give Auto - Med ( requiring a small stock of Holy Water ) is useful for this . Quickly dispelling Seymour ' s Reflect when he casts it on himself will prevent him from bouncing Flare on his next turn . It is unwise to cast Slow on Seymour , as he is immune and Mortiorchis will counter with Slowga on the party . However , neither part will attack twice in a row — if either part gets two turns in a row , it will do nothing on the second turn . This can be exploited by inflicting a combination of Haste and Poison on Seymour . Seymour is vulnerable to Wakka ' s Silence Buster which will prevent him from casting Flare , Reflect , Dispel , and Protect , effectively wasting his next turn each time he is silenced . When Seymour begins charging Total Annihilation it is recommended to cast Shell ( or Kimahri ' s Mighty Guard or one of Rikku ' s " Mighty " Mixes ) on the party members with the highest HP and then defend before he executes this . Hastega , and aeons prepped to have full Overdrive gauges , are a big help . The aeons will have few turns before being banished by Seymour , but Shiva ' s Diamond Dust does quite high damage to all targets , and Bahamut ' s Mega Flare can break the damage limit . A good strategy is casting Bio and then summoning . It is possible to defeat Seymour using only the aeons ' Overdrives if Yuna has Yojimbo and all the Overdrive gauges at full at the beginning of the fight . Mixing two Underdog ' s Secrets ( 99 of them can be obtained from Rin in " Fahrenheit " if the player has learned all the Al Bhed language ) , can also break the damage limit . Etymology . Seymour Flux is known as " Seymour Beta " in the Spanish and Italian versions , " Seymour Sublimé " ( Exalted Seymour ) in the French version , and " Seymour Obscura " ( Dark Seymour ) in the German version .