Right, I'm not sure what his name is, but he's the one that heals 2,000,000 if I'm not mistaken and is impossible to kill (pretty much). Here's how I killed him in less than a minute:
Before you fight him, get the Subversion ability from the ability tree, then go ahead and face him.
Land a few quick strikes on him (1-5 depending on your average damage, just before he starts healing himself - stop damaging him) then use Subversion.
He should do 2,000,000 damage on himself instead of healing.
Useless tip: If you don't have enough ability points for Subversion, just Re-Spec!
