Phase 2 is physical phase. I need a Lifeline up since he counters everything with Chaos Zone, which obviously OHKOs my party. I take it very easy because it's easy to mess up timing and not get a Lifeline up before DD's next normal attack. Also, I know for certain that your actions before DD's next turn will alter his next move, aka you can easily manipulate the AI. By attacking fewer times, I happen to induce fewer Incinerates, Ice Lances, and Phantasms (none at all in this video). After he casts Starfall (energy orbs attack), he'll only follow up with single target attacks, like Barrier Change and more Starfalls, so that's the best time to strike. Slow down again after he sets aside his defenses again.
It's a real pity we didn't see Phantasm. It disses out 9999 damage to the whole party and is funny to watch. I hope you enjoyed watching 9001 Lifelines and Megaelixirs.
Vote 3!