Oh, and also: Riovanes Castle's rooftop. Because the battle hinges entirely on the Assassins getting as few turns as possible, as they will completely wreck you (and likely kill Rafa for an instant game over) if you let them get even a couple turns.
Elmdor is also amazingly annoying with his Hamedo, but the Assassins are lethal, and all 3 enemies in the battle are faster than nearly everyone in your party unless you modify it specially for that fight (and I hope you have speed enhancing equipment or the Ninja class...).
**PS3 ID: GenocideHeart - Vita ID: VR-Jaguarandi** "You forgot to buy Warp Wire, didn't you?" --Nevius
Agree with TC Omega Weapon in VIII was hard. If you don't cheat with Heroes/Holy Wars that is. He wasn't the hardest though that honour probably falls to the FFX superboss Penance. And before anyone posts about cheap tricks/cheats to beat them i'm going by actually battling them without outside help.