Since the Hellfire High Council is directly accessible from the Hellfire Antechamber, the fight shares the Antechamber trash with several other bosses. This small room has several packs containing a few types of enemies.
Hellfire Guardians attack tanks with Fel Strike, and will use Shield Leap Impact to rush to and damage players at range
After Shield Leap Impact, the Guardian gains Empowered Fel Strike, and tanks should use a CD to survive.
Fel Hellweavers will channel Hellweaving on random players, which healers should dispel. Hellweavingcannot be conventionally interrupted, but stuns, incapacitates, knock-backs, and other similar effects will also break the channel.
Fel Hellweavers also cast Fel Fireball at random targets; and they summon an Orb of Destruction that players should move away from.
Fel Touched Seers will cast Fel Cauterize on their allies, dealing 10% of their life in damage, then healing for 5% of their life each second for up to 8 seconds unless the Fel Cauterize buff is removed.
Seers also cast Fel Lava Beam at tanks, which will chain to up to four additional players, typically the melee DPS.
The Shambling Hulk casts Fel Slam approximately every 20 seconds, creating a line of Fel Geysers in front of him; players within 3 yards of these Geysers will take moderate Fire damage and be knocked back.
Additionally, Shambling Hulk will cast Brutal Shout, dealing raid-wide Physical damage. This ability is used more frequently as the Hulk reaches lower health.
Players should prioritize Fel Touched Seers since these enemies heal their allies, and should be sure to interrupt Fel Cauterize or use offensive dispels to remove it from enemies. The next highest-priority target should be the Shambling Hulk, then Fel Hellweavers, then Hellfire Guardians.
In the south passageway to the Court of Blood, players will additionally encounter Fel-Starved Trainees and Gorebound Assassins.
Fel-Starved Trainees are accompanied by Fel-Touched Seers. The Trainees deal melee damage and buff themselves with Fellust.
Gorebound Assassins are stealthed, and when a player walks into their range, will de-stealth and use Cheap Shot on the nearest target.
Cheap Shot stuns the targeted player for five seconds, and the Assassin will fixate their melee attacks on that player for the duration of the stun.
Additionally, Assassins will periodically target a random player with Fel Poison, which can be removed by poison-dispelling effects such as Cleanse or Detox.
There is also a mini-boss, Graggra, on the landing between two flights of stairs immediately outside of the Court of Blood. Players can skip Graggra by hugging the right side of the staircase. If Graggra is engaged in combat, she will use the following abilities:
Bad Breath is a cone attack she will cast at the current tank every 12 seconds, dealing heavy fire damage and leaving a debuff that increases fire damage taken by 200%
Tanks must swap duties after each Bad Breath to avoid ever taking Bad Breath damage while debuffed
Graggra will target all players with Blazing Fel Touch, placing small green felfire spheres over the players' heads
After 30 seconds, the Blazing Fel Touch will erupt, dealing damage to all players within 6 yards
Players will get a green circle around them when there are 5 seconds left on the Blazing Fel Touch debuff, to indicate the size of its explosion
The raid must spread out to avoid splashing damage on other players
Graggra will also target one player with Graggra Smash, placing a green arrow over their head and a large circle around them, and leaping to their position after 5 seconds
This deals very heavy damage, split between all players within the impact zone
The raid must stack in the circle to split the damage, but be mindful of the timing on Blazing Fel Touch and spread back out immediately after
Note that at the top of the stairs just to the right of Graggra, there will be three stealthed Gorebound Assassins moving as a pack. This group is very dangerous, especially if pulled while players are fighting Graggra.