Any tips on killing the Watcher in Requiem?

[martydosh]

Okay, so I've thrown everything at the guy, and the best I can do is get him to turn to stone AFTER he's killed Mazzarin and the rest of my troops are getting pounded to the ground by the Taken and Thrall. Sacrificing satchel dwarves, whirlwinds, paralysis arrows... nothing seems to make a dent. How do you do it??

[Gleep]

If you kill the black thrall that are following him, it hurts him significantly. Focus on the thrall, then the watcher.