Lady Deathwhisper
Health: 3,000,000
/13,400,000
Mana: 3,000,000
/14,000,000
10 minute berserk timer
Mana Barrier - Absorbs all damage done to Deathwhisper, draining mana instead.
Shadow Bolt - Up to 9,562
/11,812
/11,812
/14,625
shadow damage to a random target.
Death and Decay - 4,500
/6,000
shadow damage per second you stand in it
Dominate Mind - Mind controls 2
/3
players for 12 seconds, increasing damage by 200% and healing by 500%.
Dark Empowerment - Empowers one of the adds, making them immune to interrupts.
Frostbolt - Up to 43,050
/47,150
/53,300
/61,500
frost damage to the tank, interruptible.
Touch of Insignificance - Reduces her current target's threat generation by 20%, stacking up to 5 times.
Adds
Cult Adherent/Reanimated Adherent
Curse of Torpor - Curse that increases a random target's cooldowns by 15 seconds.
Frost Fever - Disease that inflicts up to 2,625
/3,225
/3,225
/3,587
frost damage every 3 seconds for 15 seconds and reduces attack speed by 25%.
Deathchill Bolt - 8,062
/10,212
/10,212
/13,437
shadowfrost damage.
Dark Martyrdom - 12,000
/25,000
/25,000
/50,000
shadowstorm damage to everyone within 15 yards.
Shroud of the Occult - When empowered by Lady Deathwhisper, this spell reflects, prevents interrupting, and absorbs 50,000 physical damage.
Deathchill Blast - With Shroud of the Occult, does 10,750
/13,437
/13,437
/17,200
shadowfrost damage to everyone within 10 yards.
Adherent's Determination - Once the Cult Adherent is reanimated into a Reanimated Adherent, it becomes immune to magic damage.
Cult Fanatics/Reanimated Fanatics
Necrotic Strike - 70% weapon damage and applies a debuff that absorbs 9,000
/14,000
/14,000
/14,000
healing.
Shadow Cleave - Up to 15,750
/17,587
/17,587
/21,000
shadow damage in an arc in front of the fanatic.
Dark Martyrdom - 12,000
/25,000
/25,000
/50,000
shadowstorm damage to everyone within 15 yards.
Vampiric Might - When empowered by Lady Deathwhisper, this increases all damage done by 25% and heals the fanatic for 300% of the damage inflicted.
Fanatic's Determination - Once the Cult Fanatic is reanimated into a Reanimated Fanatic, it becomes immune to physical damage.
Vengeful Shade
Pursues a random target.
Vengeful Blast - When a vengeful shade catches its target, it does 18,630
/20,700
/20,700
/24,840
shadowfrost damage to everyone within 15 yards.
Strategy
In phase 1, DPS must eliminate her mana shield by doing damage to her. Once her mana shield is down, you enter phase 2 where you can kill her.
Phase 1
In phase 1, Deathwhisper is untankable and casts
Shadow Bolt,
Death and Decay (note that her version of this spell is green),
Dominate Mind, and
Dark Empowerment. She will also reanimate a dead Cult Adherent or Cult Fanatic into a Reanimated Adherent or Reanimated Fanatic respectively.
Cult Adherents and Cult Fanatics spawn in waves 5 seconds into the fight and every minute thereafter. 7 total adds spawn, with no more than 4 of each type spawning. 3 spawn by the gate to the left, 3 to the right, and one behind at the bottom of the stairs. While alive, they can be crowd controlled and snared. The tanks must pick these adds up, and DPS must bring them down.
Every so often, Deathwhisper will reanimate the dead. They spawn from where they died. Again, they must be picked up and tanked. The twist is that the Adherents will be immune to spells and Fanatics will be immune to physical damage.
Don't go crazy with AoE when people are mind controlled, as we don't want to kill off the raid. Only AoE when there's no mind control, or the mind controlled are out of harm's way. Remember to CC those who are mind controlled.
Things to watch out for are
Death and Decay,
Curse of Torpor (curse, must be removed immediately),
Frost Fever (disease), and when the adds get close to dying they will blow up. Get away from adds casting
Dark Martyrdom.
Don't kill Deathwhisper just after a wave of adds come, wait for about 100,000 mana, then bring the next wave of adds down, then bring her into phase 2. Note that phase 2 is an aggro wipe, and a tank must pick her up.
Phase 2
In phase 2, Deathwhisper casts
Frostbolt,
Death and Decay,
Dominate Mind, and
Touch of Insignificance. She also will bring up Vengeful Shades from the dead adds from phase 1. Adds stop spawning in phase 2.
Touch of Insignificance makes it difficult for a tank to hold threat, so all of the tanks must try to be right up there in threat. Tanks will switch, perhaps often at first, but less so as the fight wears on.
Like Kel'Thuzad,
Frostbolt MUST be interrupted. It does too much damage for a tank to survive.
When Vengeful Spirits spawn, they will chase someone. Ranged DPS must kill them, and the person being targeted must run away or else large AoE damage will occur.
Mind controls continue throughout phase 2, just kill her.