I’m going to break these up into Melee and Ranged, because we do have slightly different jobs for phase one.
Melee Phase One:
Be prepared to rage at tiny hit boxes.
The way we handle this in 10s, both melee peel off the boss to follow the add tank. You’re worried about two things here: 1) interrupting Depravity (OMG IMPORTANT) and 2) not accidentally killing the add before the tank drags him back to the doors. Once the add is dead, run back to the boss and DPS as normal.
Be sure to keep an eye out for people who are worshipped so that you can give them a good whack as you go by. With an interrupt, mind you, no matter how tempting it is to do otherwise. Sometimes your fellow melee will get worshipped on the way back and stand there worshipping away because no one is paying any fucking attention to shit behind them.
While on the boss, there’s really nothing special to consider except interrupting worshippers when you can. Oh and not standing in things. But really, should I have to include things like “don’t stand in fire and dark puddles on the ground” at this stage?
Ranged Phase One:
When the adds die up by the door, the dark puddles they drop on the floor will spawn oozes. The oozes need to die. The melee should, ideally, never even know they exist! Otherwise pay no attention to the ugly adds that SPAWN the oozes–that’s the melee’s job. If there are no oozes up, DPS the boss.
Interrupt any and all people worshipping when you can.
Don’t stand in things on the floor.
Phase Two, Both:
Kill all the stalks and interrupt their casts. Once they are dead, flail wildly at the boss until there’s more stalks.
This is a good time to blow Army and other tasty cooldowns.
If you have corruption sickness, do try not to vomit on people, they don’t appreciate that.