And that's what we play this game for

He's just after Craw Stonereap - you may take a look at my previous post regarding him on how to find him.
The build is in the video. It's not optimal, but it does the job.
I'm only using 3 Warrior Skills, 5 Mesmer Skills and a Necro Wand for the extra energy. Sounds silly, but I don't feel like making a mesmer to take him down.
The Build:
Skills:
Dolyak to not get knocked down, and Heal Sig to heal up if necessary.
Shatter Hex to get rid of Craws Hexes once aggro is lost
Shatter Enchantment to finnish him off when he's low enough on HP
Drain Enchantment to gain a wee bit of energy
Main Damage comes from Backfire
Conjure Phantasm is in because I played around a bit with it, but it's not necessary
Sprint to get to him. You may cut the video short and skip to the last 3rd of it, I've added a failure in it aswell, since Craw snuk up on me from behind while I was too lethargic to realize it. The vid may seem long, as it takes a while to take him down.
Clickety