The Curator (patch 2.4.3)

Fifth boss of Karazhan.

You should group up with the other healers/casters. The boss will summon an astral flare (floating arcane orb) with 12k health that comes towards the group every ten seconds. It deals arcane damage to 3 people in melee range of the flare. Simply chain heal the group thats taking damage from astral flare.

Every now and then, the boss will hit the person with the 2nd highest threat with Hateful Bolt. It average about 5k arcane damage. It can easily be healed.

The boss will use evocation immediately after the 10th astral flare. During this time, the boss takes 200% extra damage from anything your raid throws at it. The boss' evocation lasts 20 seconds long, and it is best that you use bloodlust about 5 seconds before evocation starts (boss mods will tell you the time left before evocation). You want to use bloodlust before evocation starts because the boss will summon one last astral flare before he goes into evocation, and the raid should take down the astral flare otherwise things can get ugly. The boss does not attack or use any ability while he is in evocation.

At 15% health remaining, the boss will enrage. He will stop summoning astral flares, and you should use big heals on the main tank. He will use Hateful Bolt at a faster rate so keep an eye on the person tanking Hateful Bolt.

-Always earth shield the main tank

-Use searing totem, and use fire elemental when the boss is getting close to 15%

-Use bloodlust at about 5 seconds before evocation begins

-You can dps the boss too if you want during evocation since he does not attack at all during that phase