How do I beat Nemesis?

[Yuriev's ghost]

Nemesis' defense was low enough that it always caused 99999 damage per hit for me with max strength. It was only for a few certain Dark Aeons (Dark Yojimbo, Dark Anima and Dark Bahamut iirc) + Penance where it caused less.

Blitz Ace hit for less damage though, at around 70000 per hit.

EDIT: Link of battle I found where where Attacks Reals caused 99999 damage per hit against Nemesis.

2nd link for better picture.