Killin' a Lady Lich (Lady Deathwhisper)

When you walk into Lady Deathwhisper's room, she immediately starts complaining. If you've ever shared a roof with a woman, this is a familiar event, and you know how to handle it. Just ignore her and keep clearing trash.

Like Kel'Thuzad, half of the fight is spent fighting adds while the lich herself watches. Unlike Kel'Thuzad, Deathwisper can at least be attacked during this part of the fight.

Specs
Nothing particularly noteworthy, however affliction has a rough time with the adds due to basic inability to target switch in a timely manner. Caster attention on adds isn't paramount, so this is only a minor issue, but it may be a consideration you should look at.

Of bigger concern, affliction and demonology both only get about half their execute mileage on this fight, since the first half of the damage done to her goes to her mana bar instead of her health.

Macros


/target deformed fanatic
/target reanimated fanatic

Depending on the exact way your guild choses to handle adds, you can either macro these together, or you may need to have them separate. If you have them together, the highest priority target goes last. As with all /target macros, it may be worth putting your opening spell on this, but you may find yourself readjusting range on switches anyway.

Mind Controls
The debuff is called Dominate Mind. A mod that tracks debuffs on the raid configured to specifically watch for this one is a good idea. Mind controlled people do massive damage and have to be CC'd. Fear's your main tool here, but banish works on a druid or meta lock. Affliction warlocks can use spell lock to shut down a controlled caster or healer. Ideally you want a CC that can be dispelled if it's still up after the mind control breaks. 

Phase One
Like Kel'Thuzad, Deathwhisper watches the fight in phase one. But, you can attack her, she just converts mana to heal any damage you deal, so in essence you're burning through her mana bar in this phase. Caster DPS will primarily be on Deathwhisper while adds come from both sides and behind. Drain mana is not worth casting in this fight. The spell is fairly weak, and is limited by your mana pool. Health damage and mana damage are the same for this phase, and all specs can do health damage faster. Watch out for Death and Decay. It's big, bright, and green, so it's impossible to miss, and it doesn't blend in with any player abilities.

There's several types of adds on the fight, most of them are variations on Cult Fanatics and Cult Adherents. Ignore Adherents, as they become highly resistant to magic attacks. Fanatics, however, do the opposite.

Some of the Fanatics that spawn will either become Deformed Fanatics (Plague beasts) or Reanimated Fanatics (skeletons). Deformed Fanatics do increased damage and heal for the damage they deal, and focused DPS is needed to overcome their healing. When Deathwhisper yells, "I release you from the curse of flesh!" she is transforming a Cult Fanatic into a Deformed Fanatic. Adherents do not have a deformed form.

Reanimated Fanatics have a buff called Fanatics Determination, reducing physical damage by 99%. Again, it falls to casters to kill these off. When Deathwhisper yells, "Arise, and exalt in your true form!" she is raising a reanimated add, though it may not be a Fanatic, Adherents can be reanimated as well..

The last consideration in this phase is Curse of Torpor. This will put add a 15 second cooldown to every spell you cast. This isn't a problem during DOT refreshes, but it is a problem with nukes. Having macros, keybinds, or even just a separate bar on hand to swap to other nukes is a good idea. You should be getting decursed quickly, but don't risk eating a 15 second cooldown on your primary nuke, cycle through other spells while you have the debuff.

Phase 2
Once Deathwhisper's mana is depleted, she enters phase 2. "Enough! I see I must take matters into my own hands!" is your cue to break off and clean up adds.

Cultists stop spawning, but you do have to deal with any still alive. Watch out for Reanimated Adherents with the Adherent's Determination buff, they take 99% reduce magic damage and there's no point in wasting your time with them.

Threat can be an issue on this phase. Deathwhisper stacks Touch of Insignificance on her target that reduces their threat generation by 20% per stack. She is tauntable, and tanks will be switching during phase 2 to prevent this from getting out of hand. She also enters this phase with a blank threat list, residual damage left over from phase 1 can be touchy in the first few seconds. She is tauntable, however, and your job is to deal with cultists for the moment, so you should be in no danger as long as you switch off of her when her mana barrier breaks.

Death and Decay and mind controls still happen in phase 2, but the cultists are over once you kill off the spares. The new consideration is Vengeful Shades. These will follow random people. If one has you targeted, get the fuck away. If they reach you, they will explode and do a lot of damage and make people very angry at you. If you're using your portal, be very careful about where you put it that you're not screwing yourself and everybody within 15 yards by popping too close to the shade you're fleeing.

With her health depleted, too, Deathwhisper's out of cheats and dies.

The Profit
Nibelung is probably the most interesting bit of loot on Deathwhisper, or even in the zone. Proc based caster weapons are an extreme rarity. I may elaborate on this staff more in the future, but for now, I'll just say that the proc sucks... usually. On single target fights, you're better off with pure stat weapons. However, there is no internal cooldown, and during AOE every hit on every target has a chance to proc a Val'kyr to fight at your side. Casters with this staff have had several of them up at a time on AOE heavy fights like heroic Anub'arak, and it actually does start pulling it's weight. If nothing else, this one's worth picking up just as a toy.

Shoulders of Mercy Killing, hit/haste, and The Lady's Brittle Bracers, hit/crit round out the cloth drops from Deathwhisper. Mercy Killing is probably the more attractive option in terms of itemization, but the Brittle Bracers are more likely to find their way into your wardrobe because of tier pieces tying up the shoulder slot.

Ring of Maddening Whispers is a crit ring, but it's also spirit, which is a commodity in Icecrown. If you happen to be sitting on something like the ring from Onyxia's head, this is a solid upgrade.