First was straight kill Gebel so I could get the Usurper trophy/achievement. Never bothered with the end scenes as I had to close to game before any surprise saving could occur.
Second was beat Gebel to the point where the moon turned red and I had to slash it with Zangetsuto. Went to the red moon hallway, slashed that moon, and now I'm at the Den of Behemoths endgame portion of this.