Blood-Queen Lana'thel is the leader of the San'layn, The fight is a cross between a very intense DPS race and a hellish battle for survival. High raid awareness and understanding of the fight are critical, even a single player death can mean a wipe.
Blood Mirror - 50,000 yd range, 100% of damage done to you is dealt to the linked source. This affects the person closest to the tank.
Delirious Slash (Heroic mode) - 10 yd range, Inflicts 50% of weapon damage to an enemy and causes it to bleed for 4500 to 5500 damage per application every 3 sec. for 15 sec. Instant. 75% of weapon damage+6125-7825/3 on Heroic
Vampiric Bite (Heroic mode) - 100 yd range, Deals 12025 to 13975 damage to the target, granting them the Essence of the Vampyr Queen. Instant. 13875 to 16125 on Heroic. Triggers...
Essence of the Blood Queen (Heroic mode) -
100 yd range—You are infused with the blood of the
Vampyr Queen. Damage done increased by 100%.
Attacks heal caster. Instant. 75 second duration. Healed
for 10% of all damage inflicted. Attacks cause no threat. As
it wears off, triggers...
Frenzied Bloodthirst - 50,000 yd range, The caster
must satiate their need for blood, otherwise they will lose
their will to Queen Lana'thel. Instant. 15 second duration.
"Vampiric Bite" replaces the caster's action bars. If not
sated after 15 seconds...
Uncontrollable Frenzy - 50,000 yd range—Charmed. Increases
damage done by 100%. Health increased by 5000%. Increases
healing done by 1000%. Instant
Pact of the Darkfallen - 100 yd range, Deals Shadow damage to you and nearby non-linked allies. This effect expires when all linked targets are within 5 yards of each other. Instant. 5000 Shadow damage every 2 seconds. 2 targets are linked. Triggers...
Pact of the Darkfallen—Deals shadow damage to nearby
Shroud of Sorrow - An aura of sorrow and despair emanates from the caster, inflicting 4500 Shadow damage every 3 sec. to nearby enemies. Instant. 40 yard radius
Presence of the Darkfallen - The presence of vampyr kin
infuses Queen Lana'thel, increasing the power of her Shroud
of Sorrow by 5%. Heroic only.
Swarming Shadows - A swarming void consumes the target,
causing a mass of shadows to appear beneath the target and
dealing 2,313 to 2,687 Shadow damage every 2 seconds.
This creates a cloud of shadows on the ground that deals
damage to players who stand in it.
Twilight Bloodbolt - Hurls a bolt of dark blood at the target, dealing 9,250 to 10,750 damage to the target and surrounding allies within 6 yards.
Incite Terror - Magic dispellable 4-second fear on the entire raid to begin the air phase.
Bloodbolt Whirl - Summons a maelstrom of whirling Bloodbolts every 2 seconds for 6 seconds.
Bloodbolt Whirl—Hurls a bolt of dark blood at the target,
dealing 9,250 to 10750 shadow damage to the target and
surrounding allies within 50,000 yards.
She should be tanked right at her starting position. She requires two tanks, because she links her primary tank to the player standing closest to the tank (Blood Mirror), which means the linked target takes the same amount of damage as the tank. Shamans should use Tremor Totem, and it's a good idea to have all healers in a group with a shaman. If no shamans are available, Priests should Fear Ward healers.
The raid needs to stay distributed throughout the encounter (6 yards away from everyone else). It's a good idea to keep a circle of about 10 yards free of players right in the center of the room, and also to have everyone stay away from the walls. Ranged DPS make a semicircle at maximum range.
The fight has only one phase. Although every two minutes she performs a very short air phase, the mechanics of the fight remain basically the same at all times.
Every player constantly takes damage from her aura (initially 4.5k per tick, increasing with each vampire in the room).
At random intervals, a random raid member gets Swarming Shadows, which makes them drop Shadow Fire on the ground until the debuff expires. Affected players can avoid taking any damage by running. It's a good idea to keep the walls free of other players, so that players with Swarming Shadows can simply run along the walls.
Another ability which she randomly uses is Pact of the Darkfallen. This links 2/3 (10/25 man) players to each other, they take increasing amounts of damage until they stand on top of each other. Linked players should meet in the center of the room.
Every two minutes she takes off, fears the whole raid and launches three extra Blood Bolts at every player. When she takes off, ranged DPS should run to the walls of the room while melee spread out in the middle. Healers should be in a circle between melee and ranged. After the fear is over, players must spread out again very quickly, else the Blood Bolts can be lethal. Healers should move only minimally after the fear and instead start a massive spam of AoE heals right away.
The Blood Queen has an extreme amount of hitpoints and a 5:30 minute enrage timer. An average of 9.8k/7.8k (25/10 player) DPS is required to beat it (assuming 2 tanks and 5/3 healers). Virtually all raids use the Vampire debuff to boost their DPS (although it's theoretically possible to beat her without using it).
15 seconds after the start of the encounter Blood-Queen Lana'thel bites the highest threat player which is not tanking, dealing the Vampire debuff. Becoming a Vampire has the following effects:
Targets deal 100% more damage while also creating no more threat
Targets heal themselves for 10% of the damage they deal
After 75 seconds, targets must bite other non-Vampiric players or become mind controlled after 15 sec
The Blood Queen bites only one player throughout the whole fight. After 60 seconds, this person must bite another raid member. After 60 more seconds, both need to bite two more players, next four, and so on. It's extremely important that damage dealers get bitten first (starting with the highest DPS first), and healers last. DPS cooldowns should only be used after all damage dealers are bitten.
Some raids establish a fixed bite order. One damage dealer can use all cooldowns while the others hold back a little, making sure who gets bitten first. Assuming 8 melee and 8 ranged DPS, everyone biting within 3 seconds after the Vampire debuff expires, an example bite order can go as follows:
Melee 1 gets bitten
Melee 1 bites Ranged 1 who comes into melee to get bitten then moves back to range
Bite 3 melee
Melee 1 bites melee 2
Bite 3 ranged
Ranged 1 bites ranged 2
Bite 4 melee
Melee 1 bites melee 3
Melee 2 bites melee 4
Bite 4 ranged
Ranged 1 bites ranged 3
Ranged 2 bites ranged 4
Bite 5 melee
Melee 1 bites melee 5
Melee 2 bites melee 6
Melee 3 bites melee 7
Melee 4 bites melee 8
Bite 5 ranged
Ranged 1 bites ranged 5
Ranged 2 bites ranged 6
Ranged 3 bites ranged 7
Ranged 4 bites ranged 8
16 vampires are out, Bloodlust or Heroism now. It may be advisable to delay the first two rounds of biting a little, in order to avoid conflicts during the air phase - else it's possible that some players must bite during or shortly after the fear, which may mess up the bite order.
After the 5th round of bites, there's no need to bite anyone anymore, because she enrages at 5:30. With this organization no one should ever get mind controlled as long as they memorize their targets before the encounter begins. Healers should keep in mind that when a bite round is occuring, especially the final bite round people absolutely have to bite their targets even if they have Pact of the Darkfallen or Swarming Shadows. Divine Sacrifice or Aura Mastery Shadow can mitigate this if used at the right time, assuming they're available since they're also highly useful in the air phase.
In heroic mode, Blood Queen Lana'thel gains a stack of Presence of the Darkfallen for each vampire present. Each stack of this buff increases the power of her Shroud of Sorrow for 5%.
[info from http://www.wowwiki.com/Blood-Queen_Lana%27thel_%28tactics%29]