Demon Gate. I was at low HP for most of the battle, but I just kept slamming him with everything I had. Cloud and Vince were pushing it to the limit, and Aeris's cure wasn't doing much. Still, I thought I was doing pretty well. I kept telling myself "One more hit and he's dead!" But that hit never came. Finally I used Scan and found that one or two more hits would beat him. Right after that, he killed everyone. It was sad...