This is the final boss in The Voidspire. It has three phases plus two intermission phases. During the intermission phases the boss is immune and the biggest DPS check is during phase 3, which is purely single target - when we should use Bloodlust.
Phase 1 - Undying Sentinels
Three Sentinels (Morium, Vorelus, Demiar) - they will channel an AoE when they're not being tanked.
Tank Morium & Demiar.
Kill adds on top of the bosses you are fighting. Avoid the pool it drops. Increases damage taken by anything in the puddle. Dispel debuff on players.
Alleria fires silver arrows from the centre of the platform - targeted player stand behind someone with a void debuff. Each Sentinel needs to be hit by at least one arrow to die. Try not to hit any of them more than once.
Void Expulsion - orbs landing on ground. Avoid puddle.
Grasp of Emptiness - void circle on the ground with three targetable beams - point away from the raid by moving around circle.
Intermission - Sentinels Dead
Group up into one section of the platform. Run against the suck. Avoid stuff on the floor.
Phase 2
Rift add. Move away from Alleria.
Healing absorb that can be dispelled - when dispelled it jumps to the next player.
Occasional barrier on the rift add - dps it off.
Void spawns - kill before they reach 100%
TANK: Rift Slash - keep an eye on stacks and swap when needed.
Intermission - Rift Add dead
Same as first intermission plus void spheres - avoid.
Phase 3
Similar to Sylvanas fight in Shadowlands, hopping between platforms.
Aspect of the End - marked players need to move out of grey circle. This knocks them up and does raid wide damage. Stagger moving out.
Still has some parts of P1.
Devouring Cosmos: switch platforms by running over a feather at the edge and jumping over.
Kill boss before you run out of platforms!