Final Deus was awesome. I've only beaten him once. I had three GNR50 attack enhancement parts EACH equipped on Fei, Citan, and Emerelda... I was r0x0rd brutally. (Even though I won)
EVEN HARDER!!!
Tyrant/Astral Dragon combo boss from Breath of Fire IV. AT LEVEL 50!!!!! If anyone can beat this boss at THAT LEVEL in less than five hours... you are God. Tyrant had the whole shebang: HP to one, negation of special attacks and magic, basic attack dealt Instant Death, not to mention ONE MILLION FRIGGIN HIT POINTS!!!!!!!