Before we can engage Anetheron himself we will need to get through the trash waves. Below all the mobs that are in the trash waves are described and explained what they do and how we handle each individual mob. Then a list of wave-setup follows to get a quick overview and feel for how to deal with each wave on its own. After that Anetheron will follow and below you will find a short description of his abilities and how to deal with each one of them. I have added a picture from Bosskillers to the Anetheron part of this guide to give an idea on how to spread out.

Trashmobs on Anetheron

Looking at the waves on Rage Winterchill and Anetheron theres only a few simple concepts we have to take into account. For the Anetheron fight we will have Banshee's join in, they are not so difficult to handle so it is not a big addition. For the mobs I have only listed the abilities that are important to know about during the trash waves.

Ghouls, Abominations and Crypt Fiends
A Hunter kites a Ghoul/Abomination/Crypt Fiend (preferably a Ghoul) towards the NPCs to engage them into the fight, when that is done they kite the mob(s) back through the AoE. The AoE groups consist of Ghouls/Abominations and Crypt Fiends, any class that can AoE will be helping out on these mobs.

Ghoul special ability
Cannibalise - When they go low on health, the Ghouls will run to a corpse and start cannibalizing it, restoring about 7% of their health every 2 seconds, for 10 seconds. If you see a Ghoul cannibalizing, you must stun it or Shackle it or even Fear it as fast as you can to prevent it restoring health. A cannibalizing Ghoul takes an entire raid's worth of DPS to kill.

Abomination special ability
Poison Aura - Sometimes the Abomination will use a poison cloud-like ability, dealing roughly 750 damage to everyone around the Abomination every 3 seconds (basically this is nothing to worry about since only the tanks will get hit and should be healed through).

Crypt Fiend special ability
They will sometimes shoot out tiny spiders at a random person in range. They do about 300-400 damage total. Absolutely nothing to worry about and should just be healed through.

Shadowy Necromancers
A tank picks these up (a DPS Warrior will do), usually there is 1 or 2 alive and kicking so that shouldn't be a problem, anything extra is sheeped/feared. Melee will kill these mobs, it is important that they interrupt their main abilities, which is "Summon Skeletons" and "Shadow Bolt".

Shadowy Necromancer special abilities
Shadow Bolt - A bolt of shadow dealing 2250-2750 to the current target.

Summon Skeletons - Summon a skeleton from a nearby corpse. They can be either a Skeleton Invader, with 32k HP, or a Skeleton Mage with 24k HP. One is a melee type, the other one is a caster. They are no real threat, just an irritation.

Banshees
The Banshees are the mobs to be shackled, depending on the number of mobs we can decide to shackle a few. The Banshees die before the Shadowy Necromancers will, so when there are waves with both the Shadowy Necromancers will be sheeped/feared while melee will focus on the Banshees.

Banshee special abilities
Banshee Curse - Reduces chance to hit by 66% for 5 min. Decurseable.

Banshee Wail - Much like a Shadow Bolt, it causes 2475 to 3025 to the current target.

Anti-Magic Shell - Creates an anti-magic shield around the caster, absorbing up to 200,000 magic damage for 30 seconds. Can be purged.

Waves on Anetheron

Wave 1 - 10 Ghouls
Wave 2 - 8 Ghouls, 4 Abominations
Wave 3 - 4 Ghouls, 4 Crypt Fiends, 4 Shadowy Necromancers
Wave 4 - 4 Ghouls, 6 Crypt Fiends, 2 Banshees
Wave 5 - 6 Crypt Fiends, 4 Banshees, 2 Shadowy Necromancers
Wave 6 - 6 Ghouls, 2 Abominations, 4 Shadowy Necromancers
Wave 7 - 4 Abominations, 4 Crypt Fiends, 4 Banshees
Wave 8 - 3 Ghouls, 4 Abominations, 3 Crypt Fiends, 2 Banshees, 2 Shadowy Necromancers

Wave 9 - Boss - Anetheron will come approximately 3 minutes after Wave 8 comes.

Anetheron

HP - 4,200,000
Melee Strength - About 3-6k on plate.

Carrion Swarm - Sends out a green carrion blast wave in a cone of about 60 degress of the target it's cast upon, dealing 4250 to 5750 shadow damage, and applying a debuff that reduces healing DONE(not recieved) by 75%. Not dispellable, affects potions, bandages; everything. The debuff lasts 20 seconds, and the Swarm itself is targeted at a random person. Has a 60 yard range.
He uses this ability aproximately every 11-15 seconds. (Variable timer)

Inferno - Cast every minute on a random target. A meteor falls from the sky, dealing 2,500 fire damage, stunning the target for 2 seconds and summoning a Towering Infernal where it lands. The Towering Infernal has 220,000 health , doesn't hit hard, but has an Immolation dealing 3325 to 3675 fire damage every 2 seconds to everyone within 8 yards.

Sleep - Sleeps up to 3 random targets for 10 seconds. Dispellable by Tremor Totem or Will of the Forsaken.

Vamperic Aura - Heals Anetheron for 300% of the damage he deals. Your rogues need to keep Wound Poison fully stacked on him at all times to limit the impact of this ability. Any other class that can put up healing-reducing spells should do so, Warrior's Mortal Strike, Hunter's Aimed Shot etcetera.

How to do deal with each ability
Melee Attack - About 4 dedicated healers should be enough to keep the tank up, however I will leave this up to Stellvia to fine-tune.

Carrion Swarm - This can be dealt with by good positioning. Healers should not be closer than 20y from each other, so they will be standing in a circle-ish form around Anetheron and the MT. No more than 2 healers should be affected by the Carrion Swarm at all times to keep it safe.

Inferno - The person that gets the debuff will run towards the tank and the tank can start running towards this player as well. When the Infernal lands the tank picks it up and moves it towards the killspot, as soon as the tank has enough aggro the ranged DPS switches to the Infernal and kills it to then switch back to Anetheron. 2 Healers on this tank should be enough, most strategies don't mention FR gear but medium FR gear can help a great deal to ease the healing, however our first kill try was without FR gear whatsoever and seemed to work just fine.
DPS will be spread out between the Boss-killspot and the Inferno-killspot to allow quick switching and yet good coverage of the ground (to minimize the effect of Carrion Swarm).

Sleep - Nothing to worry about really, it can get unfortunate if 3 healers get sleeped so Shamans can decide to drop Tremor totems at certain times when they think it is needed.

Extra

This is roughly how we will be positioned, however the Inferal-tank healers can position them amongst the spread ranged DPS so they can heal the raid as well when there is no Infernal up.