Hey, it's Epilogue, not Ending

Oh, that's easy. You just have to kill Khrima without using I-Buster or losing a party member. If you do that, Karn's final strike will seal him in an orange ball of holy seal-yness. During the speach in Bystandaria, hit Circle twice, Square, Triangle, Square, Square, Circle, Triangle, Square, and the secret Hexagon key. Then do a quarter-circle up while holding R1 and L2, and holding Up on the right stick about halfway. Lick the screen during Karashi's epilogue, and Argent will rise from his grave to help you fight Necrevil.