This is the Warlock Class Tree, that I made, from a section of the Hero Guide over at the community discord. Decided to post the image here, for those who don’t have discord and just want to know the Warlock information.
This is my opinion:
At this moment, in order of strength for Arena .
Charm: Always fun when enemies Hero attack teammates.
Doom: Damage attack is always good, debuff lackluster.
Blood Pact: Could be useful on prolonged fights, proper strategy required to make most of it.
Soul Harvest: Very unimpressed, by the time you get the buff for defense, most of the enemies are dead. Rendering this a waste of time.