Forgotten Experiments Raid Guide in Aberrus, the Shadowed Crucible

I also have my own website dedicated to both tanks and raid leaders where I share my insight on the bosses with strategy and preparation advice which I will update after my guild has completed progress. If you are interested in this or want to discuss it on Discord, the links to them are below:

• https://www.tanknotes.com
• Discord Invite Link

As this fight is very static in how it plays out, I've provided a raid plan link to show a step-by-step visual explanation for movement on this encounter. Click the numbered tabs at the top of the page to work through the boss encounter.

• RaidPlan Link

• Tanks: Swap at 3-4 stacks of Infused Strikes. When both tanks have stacks, run into each other to clear your stacks. Note: this applies a 20 second DoT on the raid ( Infused Explosion). Do not clear again until this DoT has expired.
• Players with Rending Charge should move away from the boss.
• Players without Rending Charge should not be in the path indicated by the arrows on the ground.
• Heroic: Rending Charge bleed is now lasts 30 seconds.
• Mythic: Rending Charge bleed is now permanent and can only be removed with bleed removal effects such as Blessing of Protection, Cauterizing Flame or a Dwarf Racial ability.
• Avoid Massive Slam.
• Run away from the boss during Bellowing Roar.

• Use Bloodlust / Heroism in this phase to reduce the amount of Unstable Essence on the raid for the rest of the fight.
• Healers: Violent Eruption deals raid wide damage.
• Heroic/Mythic Healers: Violent Eruption damage is multiplied for the amount of Remenants active.
• Dodge pools created by Volatile Spew.
• Unstable Essence is a permanent DoT placed on a player and deals more damage with every tick. When this debuff is dispelled, it will jump to the nearest player.
• As the phase goes on, more players will have Unstable Essence's.
• Heroic/Mythic: Unstable Essence will spawn an Erratic Remnant when dispelled. These need to be killed as a priority before they explode.

• Run into Temporal Anomaly to prevent them from going into the boss.
• If Temporal Anomaly reaches the boss, they will get an absorb shield making the fight last longer.
• Players with Disintegrate should spread away from others.
• Deep Breath is triggered twice per cast and is always cast on the location with the most players. Move out of the area the boss is in.

The key mechanic of this phase is to manage the bleed stacks on the raid by making sure all of the Rending Charge lines are away from other players.

Tanks: Every boss will apply a stacking debuff on you Infused Strikes. This debuff is permanent however can be removed by running into another player with Infused Strikes. Swap at 3-4 stacks of this, and when both tanks have stacks, run into each other to clear your stacks. When you clear this debuff, it applies a 20-second DoT on the raid ( Infused Explosion). Do not clear again until this DoT has expired.

• 3 players will be targeted by Rending Charge. These players should move away from the boss and make sure that the lines that connect them together do not go through each other.
• Players without Rending Charge should avoid the path indicated by the arrows on the ground.
• Typically, after the charges, the boss will cast Massive Slam towards a random player. All players should move out of this cone.
• A little while after the slam cast, the boss will cast Bellowing Roar. This deals drop-off damage, so players should run out of the circle graphic to take as little damage as possible.
• The mechanics will then repeat until the boss is defeated.

Heroic changes:

• Bleeds from Rending Charge now last 30 seconds.

Mythic changes:

• Bleeds from Rending Charge are now permanent.
• These bleeds can be removed with bleed removal effects such as Blessing of Protection, Cauterizing Flame or a Dwarf Racial ability. Alternatively, they can be immuned off with Ice Block or Divine Shield.
• Thadrion will enter the fight when Neldris is at 50% HP.

The key mechanic of this phase is to manage the Unstable Essence debuffs on the raid. As the phase goes on, more players will have Unstable Essence on them, making it more difficult for healers to keep up with the increased demand for healing and dispels.

• Use Bloodlust / Heroism in this phase to reduce the amount of Unstable Essence on the raid for the rest of the fight.
• Healers: Violent Eruption deals raid wide damage.
• Unstable Essence is a permanent DoT placed on a player and deals more damage with every tick.
• When this debuff is dispelled, two things will happen:
  1. 1: A 12-yard explosion is triggered. Move out of this to avoid taking lethal amounts of damage.
  2. 2: Unstable Essence will jump to the nearest player.
  3. Note: When multiple people are dispelled with Unstable Essence on the same location, they are not able to receive each other's debuffs.
• Volatile Spew will create lots of small puddles on the ground. Dodge these to avoid taking large amounts of damage.
• The mechanics will then repeat until the boss is defeated.

Heroic changes:

• Unstable Essence will spawn an Erratic Remnant when dispelled. The Erratic Remnant will attempt to cast Erratic Burst, which will deal a very large amount of damage to the raid. These need to be killed as a priority before they explode.
• Healers: Violent Eruption damage is multipled for the amount of Remenants active. Aim to not dispel people when this is about to be cast.

Mythic changes:

• Rionthus will enter the fight when Thadrion is at 50% HP.

The key mechanic of this phase is Temporal Anomaly. This final boss is fairly light on mechanics by itself. However, you have the debuffs from Phase 2 ( Unstable Essence) to manage still making the phase slightly more complex.

• Temporal Anomaly's will spawn throughout the phase. These orbs will constantly float towards the boss. >If Temporal Anomaly ever reaches the boss, they will gain a 5% absorb shield making the fight last longer.
• Riothus will cast Disintegrate on several players. During the wind-up of the cast, the targeted players will have a small circle around them , indicating the area where they will hit other players with this mechanic.
• The targeted players should spread away from others.
• When Riothus reaches 100 energy, they will cast Deep Breath. The boss will fly to the edge of the room, and where they fly to is where they will cast a Deep Breath. Move out of this third of the room, and wait for the boss to move again. Once they have done their second Deep Breath, the mechanic is over.
• Deep Breath is always cast on the location with the most players.
• The mechanics will then repeat until the boss is defeated.

Heroic changes:

• Temporal Anomaly now shields the boss for 10% HP.
• Unstable Essence should not be dispelled during Deep Breath so you have time to kill the adds without interruption.

Mythic changes:

• Running into Temporal Anomaly will apply a debuff making you take increased damage from it.

The strategy that had success on PTR was to not commit any major DPS cooldowns on the pull but instead save any cooldown that was 2+ minutes for Phase 2. In this phase, you will use Bloodlust and all DPS cooldowns to kill Thadrion before as soon as possible, as this is the most dangerous boss.