The last part of the final battle is with Ultimecia's final form. She will constantly use Hell's Judgement to reduce your HP to 1, so keep at the limit breaks, and use aura when you need to. When her HP reaches a certain level, her bottom half will appear, meaning Ultimecia is about to use Apocalypse, which you can draw from Ultimecia's bottom half. This is the only time you get to use this spell in the entire game. Keep hitting her, and she will go down once she is finished talking.
