This fight is again trivial. Everything about this fight is trivial actually. I sort of expected more of a challenge.
With that said, the 2 biggest (yet still trivial) issues here are:
1. The adds that spawn occasionally. They don't do much damage at all and should be taken down as soon as possible
2. "Darkness of a Thousand Souls" is a spell that he casts during the later stages of the fight. The spell does a moderate 45k ish damage. But it has a long cast time so there is plenty of time to prepare.
Aside from that, the only other issue is his large health pool so the fight takes a long time.