Overview
Three fountains ring a Malignant Cavity in the floor: flame, blood, and shadow. Imbibe empowers the two closest, stacks an infusion that doubles that school of damage and inflates those adds' health, and lasts about 90 seconds. Never drink the same pair twice. Carry one fountain and add one new: flame and shadow, then shadow and blood, then blood and flame. The blood fountain sits farther back. Walk him all the way to it. Crossing the painted line still leaves flame and shadow closer, so he drinks those again.
Every drink spawns living venom that walks to the cavity. If any add arrives, Malignant Burst hits the raid. Adds that live about 60 seconds speed up and become crowd-control immune, so kill them on spawn. Kill order is fire (Burning Venoms), blood (Clotting Venom), then shadow (Shrouded Venoms). Stay loosely stacked near the boss so targeted infections do not have to run a marathon, and aim Plague Froth's cardinal waves away from the clump. Every Catalytic Bile needs a player. Ranged stay spread around him so those soaks are covered.
Fountain of Flame
Flame Imbibe pulses Conflagrating Expulsion and spawns two Burning Venoms that tick the raid while alive. Grip them onto the other add type. Each death is a Caustic Surge DoT, so desync fire deaths so the ticks do not stack. Exploding Infection is a giant fire circle with an arrow. Run out. Distance reduces raid damage. Healers can dispel once the runner is clear to pop it early.
Fountain of Blood
Blood Imbibe pulses Hemo Expulsion and spawns one CC-immune Clotting Venom. It splits twice after death, and the children can be crowd-controlled. Siphoning Infection puts a healing absorb that player spells cannot cover. Allies stand in the circle so the victim can steal health.
Fountain of Shadow
Shadow Imbibe pulses Gloom Expulsion and spawns five shielded Shrouded Venoms. Slow them and finish fire or blood first. Deaths drop Umbral Ejection puddles. Stygian Infection trails bursts under the target. Keep moving, stay in heal range, and let healers chew the absorb.
By role
Tanks
Face him away. Between drinks, hold him between the two fountains you want next. Walk him all the way to blood. Crossing the painted line is not far enough. Swap Dripping Fangs on one stack. After the hit, help collapse adds.
Healers
Toxic Vapor is the baseline. Imbibe and Malignant Burst are the peaks. Flame infections need a pre-heal on the runner. Blood infections need bodies in the circle. Shadow infections need absorbs broken while the player kites. Call staggered fire deaths so Caustic Surge ticks do not stack.
DPS
Kill venom before it reaches the cavity: fire, then blood, then shadow. Stagger Burning Venom deaths so Caustic Surge does not stack. Finish clot splits. Spread Plague Froth away from the clump. Every Catalytic Bile needs a player, so ranged stay spread around him.
Why pulls die
Imbibe is the scripted raid hit. Malignant Burst fires if any venom reaches the cavity. Stacked Caustic Surge from simultaneous fire deaths turns the next drink into a healer check. Toxic Vapor turns later drinks into healer checks. Plague Froth clips stacked groups. Tank deaths follow Dripping Fangs without a swap. Missing the blood fountain re-empowers flame and shadow and snowballs the add health.
Questions
What happens if venom reaches the center?
Malignant Burst hits the raid. Kill every living venom on the way to the cavity.
How do you choose fountains?
He Imbibes the two nearest fountains at 100 energy. Tanks hold him between the pair you want next, and never the same pair twice. Walk all the way to blood or he drinks flame and shadow again.
What is the add kill order?
Burning Venoms (fire) tick the raid, Clotting Venom (blood) splits, and Shrouded Venoms (shadow) can wait under slows. Fire first every time. Stagger those fire deaths so Caustic Surge does not stack.