This is one of the 2 secret bosses in the game and can only be found on Disc 4 in the final dungeon, Hades. He is not to hard, just make sure to of maxed Thievery and Dragon's Crest, and have Eiko's Concentrate on and you'll be fine.
Levels:
Zidane: Lv 86
Freya: Lv 78
Vivi: Lv 82
Eiko: Lv 77
Played by: TailsGt1(me)
System: PSX(played on PSP)