Prince Malchezaar is the last fight in the Karazhan instance. This is fight that involves endurance and a lot of luck. Here's how to do it.
Set Up
First, you will want all of your raid to stand in the doorway just inside the door. The tank will tank him along the wall, just inside healing range, with his back to the wall. Have a hunter turn Track Elementals so that the raid will know where the boss will land.
The Fight
To start the fight, have a hunter Misdirect Prince Malchezaar to the tank. Everyone must do ranged damage to him, even melee players. The prince has three phases. The first is the easiest to heal through. During this phase, he attacks the tank with no weapons and casts summon internals that last for 180 seconds. They are stationary and do an Area of Effect, or AoE, spell that can be avoided. They cannot be killed. Enfeeble is one of Prince Malchezaar's other this spells during phase one. It will reduce some of the raid members to 1 health for 8 seconds. If you are hit during this time you will die. After it wears off your health returns to where it was before the spell hit you.
Shadow Nova is anther AoE that does 3000 damage to everyone in it. For this reason, the tank should be the only player around Prince Malchezaar when he is using Shadow Nova. He will use Shadow Word Pain on whoever is the highest on threat list. This does 1500 shadow damage per tick and cannot be reflected. It should be dispelled, though. During phase two, Prince Malchezaar hits harder but can be disarmed. In this phase to he switches to duel wield and no longer cast Shadow Word Pain. He will cast Sunder Armor and Cleave during this phase. During phase three Prince Malchezaar no longer does Cleave, Sunder Armor or Enfeeble.
He will cast Shadow Word Pain, still. He also uses fly axes which spin randomly at players in the raid and must be healed through. He will summon internals at a much higher rate and cast damage on a random people in the raid. Raid members will be able to kill Prince Malchezaar once he reaches this phase. To learn more about strategies for World of Warcraft, try reading the Team Idemise guide.