Whenever a Hero's Coffin spawns, Anashti Sul will despawn briefly and respawn in the center of the room facing down the ramp. When she does this, she also wipes her aggro, so tanks have to be ready to pounce and re-aggro her. Anashti Sul will spawn a Hero's Coffin at 91%, 61%, 41%, and 21%. Unlike the group missions these coffins will spawn the floor ABOVE Anashti Sul, so make sure you run upstairs to DPS it down. If you do not destroy it in 47 seconds, a miniboss will spawn and aggro the raid.
At various intervals she will cast Impertinent Dead on any Undead Pet OR Undead Illusioned player. Avoid using undead illusion during this fight if you can.
Anashti Sul will cast Holistic Health on each player who has performed a hostile action on her in the last 10 seconds. Holistic Health has 2 effects on it - One part will sap her insane regeneration, so DPS her while you have it on. However, if the timer on Holistic Health runs out, you will be Deathtouched, and An Honored Add will spawn in your place (Healer, Soldier, Spell Caster). Therefore you have to DPS her some to reduce her regen, but also remove Holistic Health before it deathtouches you. Holistic Health can be removed by entering the Yellow Aura called Lamplight, which spawns in one of the 4 corners of the room.
Every 3 minutes Anashti Sul will cast Curse of Health on 4 players. This drops their health by 75,000, but turns into an 89k PBAE if the 4 named players are healed back to full. This can wipe the raid if you are not careful with heals or if 2 players are healed in close proximity.
Lifeblood Golem is spawned every 3 minutes. These mobs hit VERY hard, and cast an 89k DD/stun called Heartbeat. Tank it away from Anashti Sul, and focus DPS on it to burn it down very quickly.
Dartain's Skull (The skull in the center of the room) will face different directions during the raid. He will emote a warning as to which direction he will fire a directional AE. Move Anashti Sul as needed to avoid Breath of Dartain which drains HP and Mana.