Doom Lord Kazzak Abilities

Abilities
Enrage
Around 1 minute timer. When enraged Kazzak will cast 6 waves of Shadowbolt Volley and get a 30% increased attack speed. It fades after the 6th shadowbolt volley.

Cleave
Enough damage to want to avoid it.
Melee DPS have to stay behind the boss if they don't want to be nearly instantly killed.

Shadowbolt Volley
You can't avoid it by going out of range but you can partially resist it.

Mark of Kazzak
10 seconds debuff that drains 5% mana each second, if the target reaches 0% mana it will explodes and kill most of your raid. Make sure everyone is above 50% mana and it shouldn't happen.

Twisted Reflection (Dispellable)
Very dangerous one, heals Kazzak when he damages someone with the debuff, this includes Shadowbolt Volley and will most likely be the reason of some of your wipes.

Thunderclap (Dispellable)
Same as warrior ability. Around 2000 nature damage and slow movement and attack speed, it can be dispelled.

Capture Soul
Everytime a player dies, it will heal Kazzak for 150 000HP. You'd better keep everyone alive if you want to kill him.

Additional Notes
A shadow protection potion when he triggers his enrage can help a lot , you can't drink it before the fight because it will only absorb the random shadowbolt volleys you get throughout the whole encounter.
Shadow Protection buff is also a must-have.

Fight
Kazzak is a pretty much straightforward fight. Just clean the zone, pull with a hunter using Misdirection on the Main Tank and get everyone in place.
Make sure you've got people in charge of the dispells (Twisted Reflection is #1 priority), and just try to DPS as much as you can without aggroing.
To kill him easily, you should have enough DPS to kill him before he's got time to enrage a second time. If he does it's still possible to kill him but it will probably be much harder because of mana issues and shadow protection potions not availables (still on cooldown).