you can kill him even with wolf. it just takes shitloads of time. same goes with otherbuilds aswell. i think ele dudu would be also pretty solid option for killing him. just dont summon.
Wolf just dies instantly.
Poison build dies terribly quick too.
Treewarden can tank him fine. But the damage is just so terribly slow.
I thought I'd down him last night. I couldn't beat the server reset, and had to leave the game with barely a smudge of life left on him. He kept summoning diablo, or two diablo too often for me to burn them down before he'd summon again. Took me forever.
And now tonight I had him down to 30-40% and had to step away because of a bleeding nose. I got back and his life was back to 100%. I've been hitting his face for more than an hour tonight, and it definitely feels like something is off, it ain't fun at all just running circles for 2 hours and see his life barely move.
Why he can spent 30 seconds doing nothing, and then the next 30 summoning 3-4 bosses + minions is beyond me. I probably dealt 10 times over enough damage to kill him only in summons.