Maybe I'll go do that challenge to practice. I'm really tired of getting to the last stage and having him do the "angry awoken" or whatever and 1 shotting my whole team.
I think the mechanic is:
Drifting off... - only use LB, nomral attacks and abilities to deal damager
Dozing off... - only use espers and spells to deal damage
If you use the other then he uses 3x Thunderous Meteor (7x magic damage) instead of 2x Meteor (2.93x magic damage).