Ok i pulled everything to him and him out of the caves and into the open. rooted him. ran a loop and then snared him. ran the rest of the mobs off and then used Vinelash Cascade to root/snare them all. came back and tagged him. pretty easy kill then. just stay out of his casting range.
He spawned in the left tunnel branching off the cave past the third dock. loc p1927 n612. Hard solo pull for druid. had to be 25 mobs on the way in. Cane