Hex Lord Malacrass, 5th Boss

He starts with 4 random adds. Possible known adds:

Ogre - Melee add, Sheep him.
Imp - Fireball Spam, possible banish or kill quickly.
Dragonkin - Flamebreath & Thunderclap, sleep him/kill quickly, if you get this add, preferrably killing is a good option.
Undead - melee and instant casts, shackle him.
Blood Elf - Heals. Interupt heals/Kill quickly.
Serpent - Posion bolts. Sleep it / kill quickly, like the Dragonkin, killing it is preferred due to your druid does not have to shapeshift.

People seem to kill 1 or 2 of the adds before focusing on the boss.

Malacrass:

Does a nasty dot that lasts for approx 15 sec and deals roughly 300-400dmg per tick.

During the fight randomly he will Soul Drain 1 random person, he will take on 2-3 abilites of that persons class. He will continue to use these new abilities till he Soul Drains another victim and repeats a new cycle of attacks.

Every minute or so he will drain everyone of their power by 1% and giving it to himself, thus increasing his size and his damage by 10%.

Tank and spank and deal with the new abilities he may gain.

Possible Soul Drains:

Druid- Thorns & Lifebloom (big heal!!!)
Hunter- Traps
Mage- Frost Nova & Firebolt/Frostbolt
Paladin- Consecrate & Holy Light
Priest- Heal & Mind Control.
Rogue- SnD & Blind.
Shaman- Fire Nova Totem & Healing Wave
Warlock- ? ?
Warrior- Whirlwind & Spell reflect.