This is the first boss in The Venomous Abyss raid.  Nek'zali the Soulcoiler has two phases of mechanics with an intermission in between. Much of this fight interacts with the Soulcoil Well in the middle of the arena. If a player dies within the Soulcoil Well or a Raised Amani add reaches it, the boss becomes empowered, making the fight much more difficult. Keep away from the well at all times! 

• Stop Amani adds reaching the well in the centre of the room.

• In the intermission, kill two echo adds whilst soaking big red swirlies.

• Anyone who didn't soak gets a small red fire circle that they need to drop on top of the previously killed small Amani adds, to stop them respawning.

• Once the echo adds are dead, Phase 2 starts, which is essentially a repeat of Phase 1.  

• Kill the boss before he gets to full energy.