Stage One: The Forces of Blood
Zul deals ~40,000 magic damage to a random player and an additional ~12,000 magic damage to that player every 2 seconds for 10 seconds. Standard random raid damage.
Pool of Darkness
A random shadowy circle will appear on the platform and if no one is standing in it, it will pulse Erupting Darkness, which deals ~18,000 magic damage to everyone within 45 yards. Only one player needs to soak the circle and will take ~25,000 magic damage every 2 seconds doing so.
Two random players will receive this debuff, telegraphed when an orange circle starts pulsing around them. After 10 seconds, the debuff will explode and deal ~60,000 damage to all players, decreasing the farther away players are from the explosion point. Affected players should run in different directions as far away from the raid as possible until this debuff expires.
Upon expiration, five Minions of Zul will spawn near each affected player and will fixate random players. If they reach their target, they will fear everyone within 5 yards for 12 seconds (Pit of Dispair). These adds must be burned down before they reach their target, but can instantly be killed if they are purged, so mass dispel is very strong to deal with them.
Forces of Blood
Adds will spawn throughout this stage in different combinations. Optimal cleave strategies will depend on HP tuning as well as the overall DPS of the raid. The general priority is Bloodhexer > Crusher > Crawg.
1) Nazmani Crusher
Occasionally casts a frontal cone. If this add reaches full energy, it casts Thrumming Pulse, which increases the damage of Zul and all other adds within 30 yards by 50% for 40 seconds, stacking. This add should be tanked away from everything else unless it can be burned down before reaching full energy, in which case cleave would be optimal.
2) Nazmani Bloodhexer
Constantly casts Bloodshard, which deals ~45,000 magic damage to the lowest health player, but can be interrupted. The Nazmani Bloodhexer will occasionally spawn an Animated Ichor, which loses 1% health every 0.5 seconds and moves toward Zul. If the Animated Ichor reaches Zul, it gives its remaining health to the boss and despawns. The Nazmani Bloodhexer should be kept away from the boss to maximize Animated Ichor travel time.
If two Nazmani Bloodhexers come within 20 yards of each other, they will heal all enemies for 10% every two seconds, which will most likely be a wipe. Although these don't melee, tanks should make sure they have aggro so they can reliably keep them apart because they move a bit every time they are interrupted.
3) Bloodthirsty Crawg
These adds have 200% life steal. If they reach full energy, they will self destruct and deal ~61,000 magic damage to all players every 2 seconds for 10 seconds. These should be stacked on the boss and look like they can be burned down relatively easily.
Stage Two: Zul, Awakened (40%)
Knocks back the raid upon transition, so players should avoid being too close to the edges. All adds from the first stage will remain until killed.
Pool of Darkness
Works exactly the same as in Stage One.
Very similar to Dark Revelation, as two players will receive this debuff, telegraphed when an orange circle starts pulsing around them. However, affected players will lose control of their character and begin walking to the edge of the platform, jumping off and killing themselves if they reach it. This mind control can be dispelled, which deals ~43,000 magic damage to the entire raid (also happens if they jump off and die), decreasing the farther away players are from the dispel point. Healers should be ready to dispel both players as they are close to the edge of the platform.
Upon dispel or if the affected player jumps off and dies, five Minions of Zul will spawn near each affected player and will fixate random players. If they reach their target, they will fear everyone within 5 yards for 12 seconds (Pit of Dispair). These adds must be burned down before they reach their target, but can instantly be killed if they are purged, so mass dispel is very strong to deal with them.
Rupturing Blood (TANK)
A frontal cone that applies a stacking debuff which deals ~22,000 physical damage every 2 seconds per stack and lasts 20 seconds. Upon expiration off the tank (or if another player gets accidentally hit), creates a gigantic pool of blood on the platform, which applies Corrupted Blood to anyone in it, a permanent stacking debuff dealing ~500 magic damage every 2 seconds per stack.
Tanks should stack the debuff as high as manageable, and upon swap should make sure they get to an edge of the platform, conserving as much space as possible when the debuff expires and the pool of blood spawns. It seems like the pool of bloods can be stacked without much trouble, making this much easier to deal with.
Locus of Corruption
Zul consumes all his energy (which he gains more of the longer Stage One lasts) on transition and applies one stack of Corrupted Blood to the entire raid per 5 energy consumed. Corrupted Blood is a permanent stacking debuff dealing ~500 magic damage every 2 seconds per stack. Completing Stage One of the encounter quickly and efficiently will help minimize overall raid damage in Stage Two.