I just beat him by spamming black magic on him, too, but I wasn't completely maxed out. All my casters either had level 3 magic or level 2 + Magic Attack Up. I was never able to take him out immediately after his third turn, like every time, he would move, then one of my units would freeze him. I kept reloading for that, and also to see if I would get new skills on Rad, Lavian, and Alicia.
Speaking of those three, where can I set the jobs that they start with? I think I might set one to Summoner instead of Mediator or Oracle (since they're both on the same tree). Is this done with FFTPatcher?
EDIT: Ok I found it. In the ENTD, on event number 110, "End of Chapter 1, Orbonne Monastery"