This is a World of Warcraft classic guide for C'thun who is the final boss in the 40-man raid, The Temple of Ahn’Qiraj (AQ40).
Overview
C'thun is by far the hardest encounter before the release of the Naxxramas which isn't released for several months. C'thun is also known as the 'guild breaker' because many guilds have disbanded after countless nights of trying to defeat him. He has an ability to crush morale and really highlight the individuals in a raid group that are the weakest links, causing alot of turmoil.
The fight is characterized by two distinct phases, in phase 1 the raid will need to defeat the Eye of C'thun after which his Body will surface marking the start of phase 2.
This guide will detail a common approach to tackling both phases and defeating the encounter. Due to the complexity of the fight, there will be many small nuances that can only be learned through repetition and real-experience in fighting C'thun. i.e. Its impossible to cover everything here.
Phase 1 - Eye of C'thun
Abilities
Eye Beam
C'thun targets a random raid member every 3 seconds and shoots a green laser at them for approx. 2600-3300 nature damage. This laser keeps bouncing from players that are hit to other players within 10 yards. Each time it bounces the damage is multiplied by 1.5.
Typically eye beam will kill every player after two bounces.
Dark Glare
Cthun targets a random raid member and begins to channel Dark Glare which is a thick red beam that extends radially from the Eye of C'thun. The beam will begin to rotate clockwise or counterclockwise 180 degrees before it stops. Any player touched by the beam will take around 50,000 damage and die instantly. It takes around 35 seconds for the beam to rotate 180 degrees and the next dark glare will begin 45 seconds after that.
Eye Tentacles
Every 45 seconds 8 Eye Tentacles spawn around the black circle surrounding the eye of cthun. These knock-back and deal damage to players that were standing on their spawn point. Immediately they will each begin to Mind Flay random targets dealing 750 shadow damage per second. They can be stunned and interupted like normal mobs. Each Eye Tentacle has 2300 hp.
Claw Tentacles
Every 5-10 seconds Claw Tentacles spawn under random players throughout phase 1. When they spawn they will deal approx. 1500 damage to the player also knocking them back. The players knocked back will get debuffed with hamstring, reducing their movement speed. Each Claw Tentacle has 1500 health.
Positions
This is the most important aspect of phase 1, apart from entering the room on the pull. Positions in phase 1 will need to be well thought-out and rehearsed by the raid prior to engaging with the encounter. Every group will be assigned to a section of the room and the diagram below should be used.
The above diagram shows 3 important things. Positioning of groups, raid marks assigned to melee players and the count of pillars along the left and right walls.
The easiest way to determine your section is to count the pillars along the sides of the room as you are moving into position. It's advisable to use The Twin Emperors room to practice positioning.
By the time each Dark Glare ends, groups will need to have swapped sides to opposite positions. Therefore players will need to become familiar with their exact positions in two sections of the room.
Groups
This is a typical group configuration which distributes healers and melee evenly around the room while still allowing for some synergistic combinations.
The Pull
The fight is initiated by a chosen raid member (usually a melee/hunter positioned at the back) running into their position as fast as possible. The first 2 eye beams will hit this person, then the rest of the raid will be put into combat and thus be targetetable with eye beams. Therefore it is important to be spread out before the third eye beam hits. This can be tricky as people will still be moving into position.
The rest of the raid should run in after the first person, staying 10 yards behind them.
The purple lines in this diagram indicate the different paths people should take when entering the room. Ranged DPS should take the outer path, healers should take the middle path and melee should take the inner path.
The Fight
Once everyone has successfully taken up their positions in the room. All dps classes should immediately use cooldowns and burn the boss since there will be no significant abilities being cast for 45 seconds.
It should be the ranged dps responsibility to kill the claw tentacle adds that spawn randomly around the room every few seconds.
Every 45 seconds the melee which are positioned around the eye should turn around to kill the small eye tentacle that spawns behind them. These should also be interrupted if they are casting.
When Dark Glare is casting the group in its line of fire needs to move either to the left or right ASAP. The raid will then move either clockwise or counter-clockwise around the room and take up alternate positions which are opposite their original starting positions.
The first eye tentacles spawn at the same time as the first dark glare.
The rest of this phase is a repeat of these steps and after 3-4 dark glare rotations, the eye of C'thun should be dead.
The raid will now have around 15 seconds to get into position for phase 2.
Phase 2 - C'thun
Abilities
Damage Reduction
C'thun will take 99% less damage from all abilities until he is weakened.
Giant Claw Tentacle
C'thun will spawn a Giant Claw Tentacle with 90,000 hp underneath a random person. Anyone near the area will get knocked away and take 3000-4000 physical damage. If no one is in melee range they will burrow after a few seconds and re-emerge at full hp, almost certainly causing a wipe. They hit for around 2000 damage and have a Thrash ability which injects an extra two melee attacks which can one-shot tanks that arnt topped off. These will spawn every 60 seconds or 30 seconds after/before a Giant Eye Tentacle spawns. One will also spawn when C'thun comes out of his weakened state.
Giant Eye Tentacle
C'thun will spawn a Giant Eye Tentacle with 36,000 hp underneath a random person. Anyone near the area will be knocked back and take 3000-4000 physical damage. They will continuously attempt to cast Eye Beam similar to the Eye of C'thun in phase 1. However they can be interupted, stunned and death-coiled. It is essential to interupt every single eye beam.
Eye Tentacles
Same as in phase 1 except they will spawn every 30 seconds instead of 45.
Stomach of C'thun
Every 10 seconds a random person will be swallowed by a tentacle and throw into C'thun's stomach which is a hidden room located beneath the boss.
Upon entering the room players will receive a debuff that stacks called digestive acid that does nature damage. The debuff is applied every 4 seconds and it is recommended to exit the room when you have between 5-7 debuffs. Each application deals 150 nature damage every 3 seconds and is not mitigated by nature resist gear.
There are two flesh tentacles in this room which have 25,000 hp each. They will melee anyone in range. Once they are both killed then C'thun will enter a weakened state for 45 seconds.
To exit the stomach you must move to the center of the black platform indicated in the diagram below. This will eject you up into the main room.
Upon entering the room players should move near the ejection platform and deal as much damage as they can to the tentacles before leaving the room once they get 5 stacks of digestive acid.
C'Thun Weakened State
When C'thun is in a weakened state he will take normal damage from the raid for 45 seconds. It should be the goal of the raid to bring his hp to under 50% during this time.
While weakened, C'thun will not spawn any tentacles and 10 seconds afterwards phase 2 will continue by spawning a Giant Claw Tentacle again.
It is important to time when C'thun will be weakened by killing the flesh tentacles in the stomach while the raid is killing or has just killed a Giant Eye Tentacle. i.e. weakening him before the next Giant Claw Tentacle spawns.
Killing the Flesh Tentacles weakens C'thun, causing it to turn purple and become vulnerable for 45 seconds. During those 45 seconds you may bring C'Thun down by roughly 1/2 of its hp with all raid alive. If there is a Giant Claw alive, don't stop tanking it. At the end of this phase, C'thun regains its shield and the Flesh Tentacles respawn in his stomach.
Most guilds will kill C'thun in two weakened phases.
The Fight
At the end of Phase 1 the raid will need to spread out at the back half of the room. Its imperative that the entire raid be in this area so that Giant Tentacles can spawn in good locations.
When the first Giant Claw Tentacle spawns it should be picked up immediately by a tank and everyone should burn it down as fast as possible.
Melee should then position themselves near the body of C'thun to anticipate killing the small eye tentacles which will begin spawning at the same time as every Giant Tentacle hereafter.
When the Giant Eye Tentacle spawns a tank needs to pick it up immediately and a warlock should initially use deathcoil to prevent it from casting eye beam. Ranged dps and tanks should be interrupting every cast. Kill these as fast as possible. While this is happening, melee will be moving around C'thun interrupting and killing the small eye tentacles.
The raid will need to continuously deal with alternating Giant Tentacles and small eye tentacles every 30 seconds until C'thun is weakened.
If a ranged DPS gets swallowed into the stomach they will need to begin killing the flesh tentacles. Healers can help heal the ranged dps which are inside to allow them to stay longer. Melee will just need to run out.
When C'thun is weakened everyone including healers will need to DPS C'thun. After he is weakened there will be 15 seconds until the next Giant Claw Tentacle and 45 seconds till the next small eye tentacles which buys some time for the raid to recover if they are behind on killing tentacles.
The raid will need to rinse and repeat, killing Ct'hun within 2-3 weakened phases.
Notes
- The entire raid should be using full consumables for every attempt including flasks, nature protection potions and shadow protection potions.
- Remember the small eye tentacles knock-back, try to avoid standing where they will spawn.
- Movement speed enchants and Swiftness of Zanza should be used to increase mobility as there is alot of movement in this encounter.
- After reading this guide watching a video will help you make more sense of the fight.
- Use addons such as CthunWarner to notify you if you are standing too close to another player in Phase 1.
Good Luck!
~Sanctus