Yeah when I got to gran pulse I farmed the crap outta the place before moving onward. It made the end game a lot easier. I did the same thing in FFXIII-2 farming for almost 3+ hours doing quick 1 min battles that were giving me 500 cp a pop. Both Serah and Noel had 5000+ hp and my monsters had around the same and still Cauis beat the crap outta me a few times. I have never sweat so hard and had my heart pounding so much after I beat a game ... not even when I got my first 50 in Halo 3 or played CoD 2 on veteran finally getting 1000/10000 gold achievements lol My copy of Lightning Returns is almost here and I suspect there will be more insane bosses to face.

I had more problems with the 3 dragons after him that kept one-shotting me because I didn't kill them fast enough.

yeah the trick with them doing the ultimate power on you was to go all sentinel. He also has a countdown on the screen so you know when he's about to blast you.