I don’t run the Shroud often.
I’ve got one tier 3, and 4 Tier 2 items on my capped chars.
I think his agro is partly random, but can be influenced for short times. Not sure.
I’ve seen some shroud runs where he faces usually in one direction for very long periods of time, but I’ve seen others where he will not stop spinning around. I assumed it was because DPS was not concentrated on one spot, or that too many people were trying to get behind him.
He seems to act like Mummies and Flesh Golems. They will turn toward you when you hit them, but will change their mind very fast.
I’m not actually experienced enough to know for sure.
He can definitely be Diploed though.