The Sixth Boss
Abilities: Digestive Acid, Eye Beam, Dark Glare
Location: In the Vault of C'Thun (9)
Type: Aberration
Strategy
Before you start the fight, you should avoid standing infront of the entrance to the room. Instead, you should stick to the outskirts, out of line of sight, otherwise you'll aggro the boss and be completely out of position. You should drink a Greater Nature Protection Potion in advance to guarantee that your potions are off CD during the fight.
The C'thun fight consists of two phases. In the first, the Eye of C'thun will appear, which is susceptible to all types of damage. In the second, the boss is protected by a hard shell.
C'thun is pulled in a unique way, as players must pair up and ride their Qiraji Mounts to each corner of the room, so that they may quickly reposition themselves during the fight. A Warrior should enter first to tank the inital Eye Beams. The makeup of your raid is also very important for this fight: each group should have a melee, 1-2 casters, and 1-2 healers or a tank.
During the fight, you'll have to deal with adds who spawn periodically: Giant Eye Tentacles (in phase 2) must be interrupted otherwise they'll cast Eye Beam, Giant Claw Tentacles should be tanked to prevent them from disappearing and reappearing in random places in the room, and eight small Eye Tentacles will cast Mind Flay on your players.
Here is the ideal raid group placement for all of phase 1:
Consult the image above to find out the best way to position your players in the room. Members of each group should spread out to prevent Eye Beam from bouncing from player to player. The boss will cast this spell on a random player every 3 seconds, dealing heavy nature damage (which can quickly kill a player if C'Thun casts back to back Eye Beams on the target).
C'Thun also has access to a devastating ability, Dark Glare. This spell first selects a random section of the room, then summons a red beam that instantly kills players located within it. To avoid this spell, note that the boss will glow red once he has targeted an area, allowing players to quickly evacuate that section of the room.
Dark Glare will turn 180° clockwise or counter-clockwise, forcing your entire raid to flee and reposition themselves diagonally opposite to their original placement (Group 1 where Group 5 would be, Group 2 now in Group 6's spot, etc....). Check the image above to make sure you get your new position right.
Phase 2 will begin once the eye is defeated, as C'Thun will cover his eye is a highly-resistant shell. The boss will randomly swallow a selection of players, teleporting them into his stomach and dealing Nature damage every 3 seconds with Digestive Acid. All tanks and healers should leave the room while your DPS focus down the first, then the second tentacles inside C'Thun's body. Once both are defeated, C'Thun will become weak to all attacks for 45 seconds, making this a great point to blow your CDs. However, be sure act simultaneously with your raid and kill all tentacles (exterior and interior) at the same time.
Loot
|
Loot |
|---|
 Cloak of Clarity |
 Mark of C'Thun |
 Scepter of the False Prophet |
 Gauntlets of Annihilation |
 Cloak of the Devoured |
 Eyestalk Waist Cord |
 Ring of the Godslayer |
 Death's Sting |
 Dark Edge of Insanity |
 Belt of Never-ending Agony |
 Grasp of the Old God |
 Dark Storm Gauntlets |
 Vanquished Tentacle of C'Thun |
 Eye of C'Thun |
 Base of Atiesh |
