Forgotten Experiments
During this boss fight, your group will face three encounters Neldris, then Thadrion, and finally Rionthus one by one. Mostly, you should prefer single-target DPS builds, but some cleave damage also will not be superfluous.
The raid group should stay away from the tanks. Tanks should try to keep Infused Strikes as long as possible to prevent the raid damage;
During the fight with Neldris, try to avoid the extra Rending Charge stacks. Run away from the boss during the Bellowing Roar cast and avoid the swirls;
When the second encounter (Thadrion) starts, use BL;
Players under Unstable Essence should survive until 6-8 stacks. After that, healers can dispel Unstable Essence (mass dispel in one spot?), and tanks should move the boss to the adds (heroic?) to get an opportunity to cleave all of them;
Healers should track the Violent Eruption, while DPS should try to kill all adds before the boss starts casting this spell to decrease damage;
Dodge the one-shooting swirls;
During the fight with Rionthus, also don’t forget about Unstable Essence, but be aware, that there is no Violent Eruption at this phase;
Focus on Temporal Anomaly when it appears;
Avoid Disintegrate and Deep Breath trajectory.