I was in shock. He's freaking LVL 15. My party like yours was all 38-39ish. I was doing well until the mad Waterga session. And then, you guessed it, freaking King Marlboros aggroed me and joined the fight as they wandered by. Freaking ridiculous. After a VERY rough area (where I fully expected a Game Over screen) I was able to pull through and finish him off without too many hitches. Surprised the hell out of me though that he was that tough. It didn't help I could not get a decent Quickening chain for the life of me.