Finally beat Seymour Flux, took me forever, like a couple days of leveling... Now I'm on to more badass bosses that will surely kick my butt several times

I've heard this is like one of the if not the hardest boss in the game, between full-life, cross-cleave, and total-annihilation, he kept kicking my butt. I got every aeon to overdrive and used bio and actually ended up killing him before even getting to bahamut, though. Mostly I just needed a good strategy to beat him.

If I didn't beat him that time I was going to come here for strategy thoughts, but I guess I figured them out on my own.