He doesn't have any special attacks but his melee Berserker Slam is devastating, IF he lands it. It's pretty easy to avoid as he takes his time about bringing his weapon down so there is time to move out of the way before his weapon lands. His weapon will land with such force that it was stick in the ground and he will take a couple of seconds to pull it free which you can use to inflict damage on him.

He can be frozen.