Heroic Imonar the Soulhunter, Hope's End

Tanks

• Taunt off one another when your Sever or Shock Lance stacks drop.
• Use active mitigation on the application of Sever, Shock Lance and Empowered Shock Lance.
• Move away from players afflicted by Sleep Canister
• Ensure that melee DPS can attack Imonar during phase two as the raid moves around as a single group.
• Avoid standing within the beams created by Charged Blasts.
• Avoid triggering any traps throughout the encounter.
• When the boss flies to the other platform, follow him and interrupt his channel once all players have arrived.

Healers

• Dispel players afflicted with Sleep Canister once all other players have moved 7 yards away (10 yards on Heroic).
• Move away from players afflicted with Sleep Canister.
• Avoid triggering any traps throughout the encounter.
• When the boss flies to the other platform, follow him and interrupt his channel once all players have arrived.
• Stack as a group and move together each time Shrapnel Blast is cast during phase two.
• Ensure that you do not face the Charged Blasts beam towards the raid.
• Avoid the Empowered Shrapnel Blast circles during phase three.
• Move to the edge of the platform if you have the Empowered Pulse Grenade debuff during phase three.
• Be prepared to heal ever increasing raid damage during Intermissions and during phase three.

DPS

• Move away from players afflicted with Sleep Canister.
• Avoid triggering any traps throughout the encounter.
• When the boss flies to the other platform, follow him and interrupt his channel once all players have arrived.
• Stack as a group and move together each time Shrapnel Blast is cast during phase two.
• Ensure that you do not face the Charged Blasts beam towards the raid.
• Avoid the Empowered Shrapnel Blast circles during phase three.
• Move to the edge of the platform if you have the Empowered Pulse Grenade debuff during phase three.

Source: Imonar the Soulhunter Antorus Raid Strategy Guide - Guides - Wowhead