Prince

Strategy
The fight with Prince Malchezaar has three phases:

Phase One
Phase One starts immediately when Malchezaar aggroes. The door to the balcony closes, and Malchezaar starts summoning infernals and casting Enfeeble and Shadow Nova. He casts Shadow Word: Pain on the tank.

Fight Malchezaar with the tank's back to the wall to avoid knockback.
DPS him steadily down to 60%, being mindful of Enfeeble, Shadow Nova, and the Infernal AoE.
One strategy is to use White damage only for Phase One, except for hunters and classes with aggro wipes. This allows the tank to gain plenty of aggro to counter the high raid DPS of Phases Two and Three, meaning the tank will never get enfeebled.
If you start to get cornered by Infernals, have your tank move to another part of the platform. Try to do this before Phase Two.
Phase Two
Phase Two starts when Prince Malchezaar is reduced to 60% health. He warps in axes, which substantially increases his melee damage. He stops casting Shadow Word: Pain and starts Parrying and Thrashing and casting Sunder Armor on the tank. Infernal summoning, Enfeeble, and Shadow Nova continue as in Phase One.

Depending on your tank, a badly timed Thrash can take out more than 12,000 health within a second. Healers need to keep the tank topped off, and at least one healer should constantly have a large heal ready to keep the tank above 12,000 health at all times. As he has weapons, he also gains the ability to Parry incoming attacks from the front. A Thrash followed by a Parry can lead to over 20,000 damage done in two seconds.
If you have trouble with tank deaths during this phase, overhealing is advisable.
DPS him as quickly as possible down to 30%, being mindful of Enfeeble, Shadow Nova, and the Infernal AoE.
A Paladin tank may find it preferrable to stop autoattack and thus avoid parries and most of the damage spikes.
Phase Three
Phase Three begins when Prince Malchezaar reaches 30% health. Melee damage on the tank returns to Phase One levels. He stops using Enfeeble, Thrash, Sunder Armor, and Parry. He continues casting Shadow Nova. He starts casting Shadow Word: Pain and Amplify Damage on random raid members. He throws his axes into the air where they fly around attacking raid members at random. He starts summoning infernals much more frequently.

Make sure the person being attacked by the axes communicates to the raid chat or on Ventrilo or Teamspeak so they can be healed. The damage they do is easy to heal through, but if ignored may cause the death of your healers or damage-dealers. The axes do physical damage and as such can be mitigated with armor. A Paladin's devotion aura is advised.
The Infernals will spawn much more frequently and Malchezaar must be killed as soon as possible. Raid movement and communication is paramount during this phase to avoid taking damage from the Infernals. Each infernal will land on a fifteen-second timer. In less than two minutes, the infernals will completely cover the combat area, leading to a wipe. Burn him down fast.
A badly placed infernal during this phase can easily wipe the raid. If this happens, don't be discouraged, since you managed to get him through the most difficult part of the fight (Phase Two).
Safe Spots
There are "safe" spots for fighting Prince. Infernals do not damage characters in these locations, although they can prevent safe retreat for melee DPS affected by Enfeeble. Prince Malchezaar's other abilities are not affected by this location. Melee characters (including the tank) can take one, and healers and ranged damage-dealers can take the other. Healers and ranged damage-dealers do not need to move at all during the fight.

The strategy involves pulling Prince to the far left wall away from the entrance. To be more precise;

Pass through the door and follow the wall on the left. Go all the way to the far wall.
Ranged characters move forward to a notch in the wall and hold there.
Melee characters and the tank move to the next notch and hold there.
It is preferable to have ranged damage-dealers instead of melee classes. Infernals may surround the safe spot so that melee characters have nowhere to run when enfeebled.

To date, Blizzard has given no indication that they consider use of these safe spots to be an exploit.

Safe Spots: http://flavaguild.com/images/karasafe.jpg or https://2img.net/h/i9.photobucket.com/albums/a60/bmkibler/princeposition.jpg

General Tips
If the raid can dispel Shadow Word: Pain fast enough, a Mage can cast Amplify Magic on the tank to make healing easier.

The range of the Hellfires from the Infernals is not nearly as big as it seems graphically, which means that there is some leeway to where you can move and avoid damage.

If you have a ranged person that is very familiar with this fight and the safe places to stand, mark him/her with a raid icon and instruct the ranged raid members to stay on top of the raid icon during the fight. This saves a lot of time explaining positioning and is very effective if the person marked is good.

The tank can use an Elixir of Detect Demon to keep track of infernals, and not get trapped. Hunters and Warlocks should turn on Track Demons to accomplish the same thing.

Melee DPS should keep an eye on infernal positions and have an escape route to use when enfeebled.
It is possible to have all ranged stand huddled together between the wall and the pillar at the right of the doorway, avoiding Shadow Nova and most infernals, while melee tanks Malchezaar at maximum range.

A paladin tank will have an advantage during phase two, since the larger amount of charges on Holy Shield compared to Shield Block can enable him to remain uncrushable during the entire fight.

A feral druid can tank Malchezaar, starting in the center of the platform. A druid in dire bear form can Feral Charge out of each Shadow Nova knockback that isn't resisted, allowing complete freedom of tanking position in order to better avoid the Infernals.

When Prince Malchezaar resets after a wipe he will completely despawn and then respawn in around 30 seconds.

Trolls can use Berserk when hit by Enfeeble to get a free haste bonus.

Priests must avoid using Shadow Word: Death while enfeebled.

Horde Paladins must avoid using Seal of Blood during Phases One and Two.
Physical damage-dealers can use Elixir of Demonslaying to great effect, especially in Phases Two and Three.

During Phase Three, the raid may run out of room to move. Given the choice between standing in range of Shadow Nova and standing in range of an infernal, it's better to move in close and take the hit from Shadow Nova. With no more Enfeeble in Phase Three, it's not always instant death.




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