So I'm on the final fight with Takaya, and I think I'm doing pretty good; I dish out ~650 damage each turn and my teammates are doing around 250-350, then all of a sudden he kills me in one hit!
Apparently I can't even cancel out his stat boosts either, so I can't save myself that way. What can I do to kill him? I've been rushing to do as much damage as possible as fast as possible, but so far all that does is make him use his Megidolaeon and kill me sooner.

-rep he is my dad

-rep bombed my dad