Introduction
This fight consists of two stages with the twins; one stage with both twins alive, and the second stage with only Lady Sacrolash (who inherits some abilities of Grand Warlock Alythess). Throughout the fight your main challenge is to manage the fire and shadow debuffs and reset them if either stack gets too high. The twins enrage after 6 minutes and kill the raid, one shotting everyone.
Raid Setup
Melee Tanks: Two for Lady Sacrolash.
Ranged Tank: One warlock tank for Grand Warlock Alythess.
Healers: This set up requires 11 healers: 3 restoration shamans, 2 restoration druids, 2 holy priests and 4 paladins. A group should consist of three paladins and their priest healer.
Melee: You want one melee group.
Ranged: Two shadow priests are needed. One for the healing on the melee tanks, and one for the ranged DPS.
Here is a suggested group configuration:
Group 1: The two melee tanks and the warlock tanking Grand Warlock Alythess ( hunters can fill the extra 2 spots).
Group 2: Healers for the main raid. Include 1 restoration shaman, otherwise, arrange according to preference.
Group 3: Melee DPS group. Include 1 restoration shaman, otherwise arrange according to preference.
Group 4: Ranged DPS group. Include 1 restoration shaman, otherwise arrange according to preference.
Group 5: Lady Sacrolash healing group (2 paladins, 1 holy priest, 1 shadow priest, and 1 restoration druid or paladin).
The healers for the Lady Sacrolash tanks must be in a group (5) together; two paladins are needed for Shadow Resistance Aura and Concentration Aura, which are needed for optimal healing, and they can Divine Shield off a lot of the damage for smoother healing on the two melee tanks. The third healer needs to be a restoration druid or another paladin. The fourth healer must be a holy priest who can heal the entire healing group on the ramp. The fifth member in the group needs to be a shadow priest to supply the healers with enough mana to heal through the phase, since all their shadow resistance gear reduces their healing abilities.
Gear Requirements
Melee Tanks: Normal tanking gear, and the PVP trinket.
Melee Tank Healers: Healers for the melee tanks during phase one will need to be wearing shadow resistance gear. The two paladins on the tanks themselves should have a shadow resistance of 315 (not counting the aura), and the other two healers should have at least 240.
Raid: Everyone in the raid will need to have their 2 minute PVP trinkets equipped to be able to enable them to escape from the Conflagration ability (see below).
Buffs and Consumables
You'll want to use potions/flasks/food/oils for this fight, as it is a push in healing and in DPS. Shadow Protection Potions are useful for phase 2, but not completely necessary.
Boss Abilities
Lady Sacrolash (Shadow Twin)
Abilities used directly on the two tanks:
Confounding Blow - Deals 8-9k melee damage and Confounds the tank target for 6 seconds (you'll lose control of your character and move back and forth in position like when a hunter hits you with Scattershot). This also causing a loss of aggro on the tank afflicted. The second tank needs to be able to pick her up when this occurs.
Shadow Blades - Deals 2500 to 3500 physical damage and puts Dark Strike on the target.
Dark Strike - Deals 1500-2000 shadow damage and applies a debuff that slows the movement speed of the afflicted player by 10% for 10 seconds, stacking up to 5 times.
Abilities used on any raid member:
Dark Touched - A debuff that causes healing effects to be reduced by 5% each debuff, stacking till 100%. It is applied by any shadow damage coming from Lady Sacrolash's abilities. Only fire damage can clear this debuff from a player.
Shadow Nova - An AoE ability applied to the player highest on the threat table of Grand Warlock Alythess that is not the tank. As such, it will normally target the DPS on Grand Warlock Alythess. It deals about 3000 shadow damage to everyone within 10 yards of the target and occurs every 30 seconds. You want this to hit everyone in the main raid in stage one to ensure that everyone's Flame Touched debuff gets reset (see below).
Shadow Image - Mini copies of Lady Sacrolash spawn by her that cannot be targeted or harmed. They despawn on their own after a small amount of time, so putting distance between the main raid and Lady Sacrolash will cause these mobs to disappear before they can reach the main raid group. They will attack any random player that they can reach within their time limit. Their melee damage (2000-3000) does shadow damage and applies the Dark Touched debuff. They can also apply Shadowfury at random intervals.
Shadowfury - This debuff is applied by the Shadow Images' melee attacks. It causes 1500-2000 shadow damage (separate from the normal shadow melee damage of the images) and stuns everyone within 8 yards for 2 seconds.