What do you get when you beat Sephiroth in Kingdom Hearts?

In kingdom hearts 2, before your final battle with zemnas, go back to hollow baston (radiant garden is now what they call it) and go to the place where axel told you about zemnas. Setheroth should be there. A short video will play. Afterwards, the battle begins.****WARNING**** setheroth is very strong if you want to defeat him you better hold up on your final battle until your level is around the high 90's.