Anub’Rekhan Abilities

2,200,000 Health
Impale - Impales a random player in the raid, which sends all players in a small AoE line around that player flying up. Deal 4800-6200 damage and drops you from a height which will deal 50% fall damage.
Locust Swarm - Casts every 1-2 minutes. Anub’Rekhan casts locust swarm that deals AoE damage around his model. Those caught in the radius will have a DoT applied that deals 875-1125 nature damage every 2 seconds and silences. The locust swarm also reduces his movement ability to 75%. During the locust swarm an elite crypt guardian will also spawn. Locus swarm lasts 16 seconds.
Summon Corspe Scarab - Anub’Rekhan can summon scarabs from any corspe, both player and crypt guardian . This is random, he won’t always spawn scarabs, but can.

Fight Breakdown

I go into greater depth of each individual class types role below, but here’s a quick breakdown of each sequential step.

Main tank leads charge and takes Anub’Rekhan to the back of the room.
DPS and Healers take up positions as indicated on map below.
Be prepared for impale as they may occur at any moment (though never during locust swarm)
Locust swarm starts, tank must kite around the perimeter of the room and take Anub’Rekhan to the other side.
As soon as the locust swarm starts a crypt guardian (elite spider) will spawn and needs to be picked up by your off tank. These should be immediately killed by your DPS.
After locust swarm stops and the crypt guardian is dead you can resume DPS on Anub’Rekhan.
At this point be prepared for impale again and a new abililty, summon corspe scarab. Since a crypt guardian body is now on the floor Anub’Rekhan may choose to summon scarabs from the body.
Continue DPS until dead. You may have to complete another locust swarm rotation back to the top of the map if your DPS is not sufficient.