This is a single phase encounter where the boss will require specific movement and deal progressively increasing amounts of raid damage.
Chain Link - This is one of the main mechanics of the fight where 2 players will be bound together by a chain. They will have a short period of time to find their partner (who will be marked with an arrow above their head), and at any point after this if they move more than 12 yard away from each other Shattering Chain will trigger and deal a lethal amount of Physical damage to both players (Should either player survive they will be stunned for 6 seconds).
[Heroic] Chain Link is cast on more players.
[Heroic] Chain Slam - The boss will immobilise a random player in the raid and after 4 seconds any player within 7 yards of this player will be dragged towards the boss and take a shared amount of Physical damage. This mechanic will require at least 3/4 people, else deaths will happen.
During testing, this mechanic was always placed on a ranged player. Therefore as soon as the players have been gripped to boss, they need to run back to ranged to prevent spawning mechanics in melee.
Giant Fists - This is the main tank mechanic of the encounter where melee damage done to the active tank will carry through to the nearest player within 5 yards. Both tanks should be on top of each other to prevent other players from being hit.
This will essentially work as two attacks, the auto attack on the initial target, and the same hit on the Giant Fists target.
Destructive Stomp - Twice in each main phase this will be cast. The boss will show a ring around himself and any players within that ring after the 4 second cast will take a large amount of Physical damage and be knocked back. Any player in melee should run out of this. Linked players should move together.
If any pillars are in this area, they will be destroyed.
Colossal Roar - At the start of the fight and roughly every 30 seconds thereafter this will be cast. It pushes all players away from the boss and deals a small amount of damage to the entire raid.
Falling Rubble - Throughout the encounter this will be cast on several ranged players. After a few seconds if anyone is within this area they will take a moderate amount of Physical damage and be stunned for 6 seconds. A Stonequake puddle will also spawn in that area which deals a small amount of Physical damage every 0.5 seconds and slows movement speed.
Hateful Gaze - When Sludgefist reaches 100 energy he will mark the tank with this debuff. 6 seconds after the boss will charge towards the tanks location and only stop when he hits an object in the room. Any player caught in the path will likely die.
• If he hits a pillar, this pillar will be destroyed and the boss will be gain Destructive Impact and be stunned for 12 seconds. During the stun he will take 100% more damage and deal a small amount of damage to the entire raid. This will also apply a stack of Crumbling Foundation to the raid which is a small amount of ticking damage which cannot be removed.
• If he hits the wall it will trigger Collapsing Foundation.
This means that if the boss does Hateful Gaze for a 5th time, it's a wipe.
Gruesome Rage - At 30% the boss will enrage dealing 20% more damage and have 20% increased attack speed.
On Mythic difficulty this fight becomes much more about execution as every mechanic is enhanced in some capacity.
Chain Link - All 20 players in the raid are linked together. This means that raid movement will need to ideally pre-planned and assignments will be required to show how people will move based on who they are linked to. Examples include: Always move to melee if you are linked there, always move to a healer if you are linked to one, always dodge to the middle of the room etc.
Tanks are always linked together.
Chain Slam - If less than 4 players are hit by this ability the boss will enrage, increasing his damage dealt by 100% and attack speed by 60%. This will require 2 groups of chain pairs to soak, the group targeted + 1 more. The Chain Slam will also apply Chain Bleed to all players hit, so you will want to keep this strictly to 4 people where possible.
Seismic Shift - Throughout the encounter this is cast where you will take a moderate amount of Physical damage, but also deal the same damage to all players within 4.5 yards. As the distance to spread has reduced to 10 yards this means you do not have much room to move around with.
Tip: Use the rings around you to indicate if you are safe from your link partner.
Fractured Boulder - After charging into a pillar, 4 Fractured Boulders will be broken off and need to be soaked. After they have been soaked they will split into 2 Fractured Debris zones which need to be soaked also.
If any are not soaked then Fractured Impact is triggered which will wipe the raid.
Tip: 1 pair soaks each Boulder, the same pair split to soak the Debris.
This section will be updated once a strategy has been devised for Mythic on live servers
Tank Damage Profile
Swing Timer: 1.5s (Curse of Weakness 1.8s)
Brewmaster a very strong choice of tank for this encounter due to Stagger.
[Mythic] DO NOT roll away from your co-tank on Destructive Stomp. You are going to be faster than them and snap your chain.
Vengeance Demon Hunter
Vengeance Demon Hunter is a strong choice of tank for this encounter.
As the vast majority of the damage taken on this encounter is from auto attacks Shield Block is very powerful. As a result of this Protection Warrior is a strong choice of tank for this encounter.
Guardian Druid is the strong choice of tank for this encounter. Very high amounts of constant mitigation and a high health pool makes it a good choice here.
Blood Death Knight
Blood Death Knight as of writing are not a very strong tank for this encounter (FOR EARLY PROGRESSION) as the spec relies on taking damage to your health pool and then healing it back up, however as the damage is constant it can become overwhelming at low gear levels.