In Berserk Abridged finale, Griffith choosing to remain disabled for the rest of his life rather than sacrificing his friends to become an powerful, immortal demon. Sadly, Word Of God says that the Downer Ending truly happened.
Judeau: So, they really offered you infinite power and eternal life if you sacrificed us all?
Griffith: Yep, that's right.
Guts: And you chose to live the rest of your life as a cripple rather than do it?
Griffith: Well, yeah, I'm mean you all just risked your lives to save me. I'd never do anything to hurt you.