This guide is intended to provide a comprehensive description of the encounter with Chimaeron in Blackwing Descent. It is targeted to anyone who desires to understand the fight mechanics.

This guide is updated for World of Warcraft 4.3.

The encounter with Chimaeron is fairly simple and very unforgiving. While DPS will probably find it easy, this fight is very demanding on the healers and requires precise coordination from the two tanks. This encounter is divided in phases triggered only by the passing of time, which is fortunate since it enables to practice the fight in a step-by-step basis.

1. General Information↑top

1.1. Health Pool

Chimaeron's health pool is the following:

• in 10-man normal difficulty: 20.7M;
• in 10-man heroic difficulty: 36.2M;
• in 25-man normal difficulty: 72.5M;
• in 25-man heroic difficulty: 127M.

1.2. Enrage Timer

Chimaeron has a 7-minute enrage timer.

1.3. Raid Composition

The following raid compositions are advised

• in 10-man normal difficulty: 2 tanks, 3 healers, 5 dps;
• in 10-man heroic difficulty: 2 tanks, 3 healers, 5 dps (including at least one with the ability to taunt Chimaeron and keep aggro);
• in 25-man normal difficulty: 2 tanks, 6 healers, 17 dps;
• in 25-man heroic difficulty: 2 tanks, 6/7 healers, 16/17 dps (including at least one with the ability to taunt Chimaeron and keep aggro).

You will understand in the rest of that guide that in normal mode, you can replace one of the tanks by a DPS with the ability to taunt and generate threat.

2. Overview of the Fight↑top

The fight consists of two alternating phases (Spread Phase and Stack Phase) followed by a third phase (Nuke Phase).

For most of the encounter, raiders should be spread out (Spread Phase) and a friendly mechanical unit (activated by talking to the friendly NPC behind the boss, prior to starting the fight) will prevent anyone over 10,000 health points from dying. A few times, the protection provided by this mechanical unit will be temporarily disabled (for slightly less than 30 seconds) by one of Chimaeron's abilities. During such occurrences (Stack Phase), everyone should stack at a designated place to soak heavy AoE damage from the boss. When Chimaeron's health reaches between 22% and 20%, he will become immune to taunt, take 10% extra damage, and reduce healing to the raid by 99%. This is the Nuke Phase, every cooldown abilities should be used then and everyone (including the healers) should be attacking Chimaeron, to ensure that he dies before killing the last raid member alive.

3. Summary of Abilities↑top

This section is intended for people who would like to quickly check the list of abilities involved in the encounter with Chimaeron and their tooltips.

1. Finkle's Mixture
2. Break
3. Double Attack
4. Massacre
5. Caustic Slime (10-man / 25-man): every time it is cast, this ability targets 2 raid members in 10-man mode and 4 raid members in 25-man mode.
6. Feud
7. Mortality: also increases Chimaeron's movement speed by 150% and reduces healing by 99%. In 10-man mode, it increases damage done to Chimaeron by 10%.

4. Pulling the Boss↑top

Initially, Chimaeron is asleep and will not engage unless he is woken up. Before attacking him, you need to talk to Finkle Einhorn, the NPC locked in a cage behind the boss. He will activate the Bile-O-Tron 800, a mechanical unit, that provides a buff called Finkle's Mixture.

This buff is critical to your success against Chimaeron, pulling him without talking to Finkle Einhorn will invariably result in a wipe. Finkle's Mixture prevents raid members from dying when they are over 10,000 health and take a hit that would kill them. Instead, their health is reduced to 1.

Once the Bile-O-Tron 800 is active, Chimaeron can be pulled by attacking him or by waiting about 30 seconds that he wakes up. At this point, the Spread Phase starts.

5. Spread Phase↑top

5.1. Abilities

Chimaeron has a melee attack named Swing that deals about 135k damage to the current tank. He does it every 4 to 5 seconds.

Break is a stacking debuff applied on the main tank. It cannot be dispelled. It increases physical damage taken by 25%, reduces healing done by 15% (mostly so that Death Knight tanks would not be overpowered in this fight). It gets applied on the main tank every four swings (from the second swing of the fight), so about every 15 to 20 seconds. It stacks up to four times maximum (safely assume that the main tank will have four stacks throughout the fight, save the first minute or so).

Double Attack is a buff that causes Chimaeron to strike the main aggro target twice on his next attack. The two strikes happen in a time window of 0.2 to 0.4 seconds. It is triggered by the swing that applies Break and applies to the next swing. This means that the tanks see it coming 4 or 5 seconds in advance (even if they are not counting the swings).

Massacre is an attack that would kill everyone if it were not for the protection provided by the Bile-O-Tron 800. Thanks to that protection, this attack only leaves everyone at 1 health. It has a 4 second cast and a 30 second cooldown. If a melee attack is scheduled to take place during Massacre cast, it will not happen, and if Double Attack is up at such a time, it can be safely ignored.

Caustic Slime deals AoE Nature damage to everyone within six yards of the randomly targeted raid member. In 10-man, the number of raid members simultaneously targeted by this ability is 2, while in 25-man, it is 4. This ability can target anyone with the exception of the main tank (read: it can target the off-tank).

In order to clarify how these abilities are mixed together, the following figure shows you a possible scenario (taken from the data of a real fight).

Here, we chose to display on two different rows the melee attacks (and their related debuffs) and the spells (Massacre and Caustic Slime).

Throughout the phase, Chimaeron does melee attacks at regular intervals. Every 3 attacks (4 exceptionally), a new stack of his Break debuff is applied on his current target and he prepares to strike twice next. In addition, every 30 seconds he will cast Massacre. He will always start casting Massacre after he did 2 volleys of Caustic Slime. After the second or third Massacre, the Stack Phase will start.

5.2. Strategy

In order to prevent AoE damage from Caustic Slime, the raid members need to be spread out (6 yards) and in range of the healers. Here are possible positions for 10-man and 25-man respectively:

Chimaeron has a very large hitbox. It should allow melee DPS to position themselves around the boss without breaking the 6 yards spacing.

From a DPS point of view, this is a very easy fight. During the Spread Phase, all that is expected from them is to attack Chimaeron.

For the tanks, the fight is not hard but very unforgiving. The main tank keeps aggro on the boss most of the time and survives to the best of his abilities. Thanks to the Bile-O-Tron 800 and his Finkle's Mixture buff, it is not very hard. The role of the off-tank is limited to taunting the boss in the 4 to 5 seconds that precede a Double Attack and surviving the two successive strikes. Then the main tank taunts the boss back and the cycle repeats.

The idea is that the Break debuff that stacks on the main tank prevents him from handling the Double Attack mechanics. Indeed, the first attack would do enough damage to kill the main tank and his health would only be knocked down to 1 as a result of the protection provided by the Bile-O-Tron 800. The second attack would kill him.

Since the off-tank does not have stacks of the Break debuff, he should be able to survive the first attack and remain over 10,000 health which would then enable him to get saved by the Bile-O-Tron 800 when the second attack strikes. The off-tank never gets stacks of Break as the melee attacks he receives do not trigger that debuff.

The fight and this phase in particular requires great attention from the healers. The protection from the Bile-O-Tron 800 means that they should only focus on getting people over 10,000 health points, except for the off-tank who must be at full health before a Double Attack. The tough part is the Massacre ability because it comes right after a succession of 2 volleys of Causting Slime. The raid members caught by these attacks must be taken back over 10,000 health before Massacre hits, otherwise they will die from it.

Important Note: as can be seen in the first figure, Chimaeron cannot perform melee attacks while he is casting Massacre. This is a double-edged sword on which you have no control. Most of the time, the Massacre cast will coincide with Double Attack which will effectively be cancelled (since the associated melee attack cannot take place). Sometimes, you will be unlucky and the two strikes will happen right before Massacre. In that case, the off-tank and the healers need to use every tool available to avoid an unwanted death.

5.3. Tips and tricks

Here are a few tips and tricks about that phase:

• Remind your raid members not to use friendly fire abilities, such as Unholy Frenzy for Unholy Death Knights, Shadow Word: Death for Shadow Priests, or Life Tap for Warlocks.
• If the phase is hard on your healers, you can have the DPS use different health-regenerating abilities to help them, such as Gift of the Naaru for Draeneis, or Lifeblood for Alchemists.
• Mages that have Glyph of Evocation can try to time their Evocation casts so that they heal themselves after Massacre or Caustic Slime.
• Break cannot be dispelled in any way.
• Use strict healing assignments: one healer to focus entirely on the off-tank, and one healer to heal each group (both for 10 and 25 man).
• A Holy Paladin's Beacon of Light on the main tank is extremely useful since it will keep him over 10,000 health without any direct attention for the entire duration of the fight.
• Sometimes, people get targeted twice in a row by caustic slime and it is IMPERATIVE to get everyone over 10,000 health before the next caustic slime even if this means using a fast and inefficient heal (like Flash Heal or Flash of Light) - though it should mostly be done through instant casts when possible.

6. Stack Phase↑top

6.1. Abilities

During the Stack Phase, Chimaeron has two abilities:

• Chimaeron retains Caustic Slime from the Spread Phase.
• Feud is a state in which Chimaeron is for the entire duration of the Stack Phase. It prevents him from doing melee attacks.

6.2. Strategy

Sometimes, Massacre will knock the Bile-O-Tron 800 offline which disable the protection it provides. When that happens, Chimaeron enters a state called Feud, which lasts the entire Stack Phase (about 30 seconds) and during which his two heads are arguing. This prevents him from doing melee attacks.

15 seconds after the beginning of the Stack Phase, Chimaeron will cast 2 volleys of Caustic Slime, with a 7 to 8 seconds delay between each volley. Since the Bile-O-Tron is offline, Caustic Slime will one-shot any player targeted by it. Fortunately, the Nature damage this ability deals is spread evenly among the players within 6 yars of the target. So the entire raid should stack (hence the name of the phase) in one place in order to soak the damage and help the healers keep everyone alive.

After the volleys, about 25 seconds into the Spread Phase, Chimaeron will start casting Massacre. During four seconds cast, the Bile-O-Tron 800 will come back online and the healers need to get everyone back over 10,000 health. After Massacre, the Spread Phase resumes and the raid members have 15 seconds to spread out before the next volley of Causting Slime.

Obviously, this phase is very intense for the healers and very straightforward for the other roles. The last four seconds are particularly demanding because the entire raid will have suffered a great deal of damage from the volleys of Caustic Slime and everyone will have to be brought back over 10,000 health in order to survive the upcoming Massacre. Needless to say, AoE healing is a must.

6.3. Tips and Tricks

In order to make that phase easier for you, you can use the following abilities:

• A Discipline Priest can use Power Word: Barrier to help reduce the damage taken.
• Aspect of the Wild from a Hunter, Elemental Resistance Totem and Healing Stream Totem (with Glyph of Healing Stream Totem), from a Shaman, provide some protection against the Nature damage of Caustic Slime.

7. Nuke Phase↑top

7.1. Abilities:

During this last phase, you need to be aware of the following:

• Chimaeron retains his melee attack and the Double Attack mechanics.
• The protection provided by the Bile-O-Tron 800 is still active.
• Chimaeron enrage and gain Mortality. This ability renders Chimaeron taunt immune, increases the damage he takes by 10% (only in 10-man), and decreases all healing done by 99%. Chimaeron also gets a +150% speed increase.

7.2. Strategy

When Chimaeron's health reaches between 22% and 20%, he will go into rage and gain Mortality. Because of it, Chimaeron will simply kill the raid members one by one in decreasing aggro order. Since healing is pointless (99% reduction from Mortality), each raid members will be attacked twice by Chimaeron before dying (and not just once, thanks to the still active Bile-O-Tron 800's protection is still active), unless they get hit by a Double Attack. As a result, the fight turns into a heavy DPS race (especially in 10-man, in 25-man, this phase is a lot easier) and everyone needs to participate, including the healers.

Every important DPS cooldown should have been saved for this part of the fight.

7.3. Tips and tricks

Avoid getting in that phase right after a Massacre because it will leave everyone below 10,000 health, with no possibility of healing them (because of Mortality) and that means that Chimaeron will only need to attack people once to kill them.

It is possible to reach the Nuke Phase right after Chimaeron enters the Stack Phase. In that case, Feud will last the normal 30 seconds but Chimaeron will not be throwing Caustic Slime. Attempting this is risky because if you fail, you might enter the Nuke Phase while dealing with the damage from Caustic Slime which might render the Bile-O-Tron protection useless (because some members might still be below 10,000).

Because of his increased movement speed, kiting Chimaeron around is difficult but not unadvised. You can also use abilities to increase survivability. Here is a list of things you can do, by decreasing order of priority:

• Spread around the room so that Chimaeron runs as much as possible.
• Druid tanks can use Frenzied Regeneration to survive one of Chimaeron's attacks.
• Warrior tanks can use Last Stand to survive one of Chimaeron's attacks and Intervene to sacrifice themselves and save a DPS player.
• Restoration Shamans can use Rockbiter Weapon to increase their threat and die before the DPS.
• Holy Priests can cast Guardian Spirit on a targeted tank or DPS.
• Have Mages use Mirror Image when the boss targets them and the boss will waste 3 swings killing the images. This is best used right after the two tanks die, if the next highest aggro target is a Mage.
• Ensure that the healers die before the DPS by having some DPS classes transfer their threat (or part thereof) to them. Rogues can use Tricks of the Trade and Hunters can use Misdirection.
• If healers are still alive after that, then DPS classes should use whatever abilities they have to permanently decrease their aggro in order to make sure that Chimaeron targets the healers. Mages can use Invisibility, Warlocks Soulshatter, Rogues Feint and Vanish, Priests Fade, Shamans Wind Shear, and Feral Druids Cower.
• If you are a Paladin, you can cast Hand of Salvation on DPS classes that cannot lower their threat, Warriors and Balance Druids for instance.
• When Chimaeron targets a Rogue, have them use Evasion so that they might dodge a few of his attacks.
• When Chimaeron attacks a DPS Caster, have a Paladin use Hand of Protection so that it makes them immune to Chimaeron attacks but allow them to continue casting.
• Have Retribution Paladins use Divine Shield when they are targeted. Holy Paladins should die first so they are not supposed to use that ability, unless the next aggro target is also a healer. Protection Paladins can use it if they are the first tank attacked by the boss. In that case, it will make the boss waste a few seconds before going to kill the other tank while Divine Shield wears off.
• Hunters can make their pets use Intervene to die in someone else's stead.
• If nothing else is available:
  • Mages can use Blink or Ice Block.
  • Hunters can use Deterrence, Disengage, and Feign Death.
  • Warlocks can use Demonic Circle: Teleport.
  • Shadow Priests can use Dispersion.

8. Heroic Mode↑top

8.1. Differences from Normal Mode

There are 3 changes between the normal and heroic versions of the Chimaeron encounter:

• Chimaeron has more health, up to 36,2M from 20.7M in 10-man difficulty and up to 126.8M from 72.5M in 25-man difficulty;
• during the Stack Phase, Nefarian removes Feud from Chimaeron, enabling him to resume his Melee/Break/Double Attack while the Bile-O-Tron 800 is offline;
• during the Nuke Phase, Nefarian afflicts every raid member with Mocking Shadows, which eventually wipes the raid.

All the other abilities hit for exactly the same amount as they did in normal mode. One mention should be made about Caustic Slime, which targets 5 raid members in 25-man Heroic, up from 4 in Normal mode. In 25-man, Chimaeron's melee swing deals an extreme amount of damage to the main tank compared to the other versions of the fight. Fortunately, this is of no concern thanks to Finkle's Mixture.

8.2. Strategy Changes

The main change is that the fight now requires two tanks (the double-attack tank and the stack-phase tank), and one DPS with the ability to taunt the boss and keep aggro. The latter tank will be referred to as the main tank.

Another important change is the new debuff that afflicts the raid in the last phase: Mocking Shadows. In order to efficiently deal with this ability, your raid will need to properly time the beginning of the Nuke Phase.

8.2.1. Tanking Assignments

• The main tank will be tanking Chimaeron during the Spread Phase and will be afflicted with stacks of the Break debuff. Because of Finkle's Mixture, the healers only need to keep that tank above 10k. That is the reason why you do not need an actual tank here, as there is no need for defensive cooldowns or damage reduction abilities. The damage increase you get by having a DPS as a main tank is crucial for beating the enrage timer.
• The double-attack tank has the hardest task because they need to taunt the boss before each Double Attack and survive it, even during the Stack Phase, when the Bile-O-Tron 800 is offline. There will only be one such attack per Stack Phase so tanking and healing cooldowns should be used.
• The stack-phase tank is required during the Stack Phase because the stacks of Break on the main tank prevent them from surviving the melee attacks from Chimaeron when the Bile-O-Tron 800 is offline. In that phase, the stack-phase tank will take Chimaeron and will use their abilities to survive. As the phase goes on, it will be increasingly harder to survive, due to stacks of Break building up. Fortunately, the stacks will drop during the Spread Phase.

8.2.2. Timing Nuke Phase

Because of Mocking Shadows, you will want your entire raid to be topped off before entering the Nuke Phase. The best timing to enter the Nuke Phase is after a Massacre (not one that triggers the Stack Phase of course, otherwise the Bile-O-Tron 800 will be offline). Have everyone hold on DPS at about 23% or 24% and wait for Massacre. After it has been cast, have everyone stack for easier AoE healing. Then you have about 15 seconds to push the boss into the Nuke Phase before he starts casting Caustic Slime. Make sure DPS players are aware of what they are expected to do.

8.3. Tips and Tricks

Hunters can and should make their pets use Intervene to absorb the first attack in a Double Attack during the Stack Phase. This will greatly aid the stack-phase tank.

If you want to alleviate the damage on the main tank, you can use several DPS players (they need to be able to taunt and keep aggro) as main tanks and have them rotate so that they spread their stacks of Break.

During the Stack Phase, you can use the fact that players afflicted by stacks of Break will not be targeted by Caustic Slime. You can keep the stack-phase tank out of the stacking position to make healing them easier. If you are using a single main tank, then it is also advised to have them stay out of the stacking position because 4 stacks of Break are going to make them take increased damage that will be difficult to heal.

Power Word: Shield is almost required for getting a kill since it is the only way to counter Mocking Shadows. In case your raid has several Discipline Priests, choose whoever makes the biggest shields. Any ability that will enable that priest to use more shields should be used:

• Innervate from Druids;
• Power Infusion from Discipline Priests;
• Mana Tide Totem from Restoration Shamans.

9. Learning the Fight↑top

Knowing how the abilities of Chimaeron will work against your raid and how to deal with them certainly helps progressing through the encounter but your raid will most likely not finish it on the first try. Raid leaders often understand the mechanics of the encounter through their research but they fail to properly transmit that knowledge to their fellow raid members.

A solution to that is to take a step by step approach to the encounter. The fight against Chimaeron is split in phases. By chance, the first two alternating phases (Spread Phase and Stack Phase), which will pose more problems to your raid than the Nuke Phase, are based on a timer. This means that you do not need to DPS the boss to learn how to survive this this alternation of the Spread Phase and the Stack Phase.

The important part concerns the first tries. As a raid leader, you need to make sure that your raid members understand the fight mechanics. We suggest you:

• Have your DPS members do absolutely nothing except spreading out during the Spread Phase and stacking during the Stack Phase.
• Make sure the tanks understand that the main tank should be on the boss all the time, except for the Double Attack which will be dealt with by the off-tank.
• Inform the healer that they should keep everyone over 10,000 health point and that they should not waste healing past that point. Also they need to be aware of the two stressful points: helping the off-tank survive double attack by healing him to full health before he gets hit and getting everyone back over 10,000 health before the Massacre that ends the Stack Phase.

Once your raid group manages to survive 2 Spread Phases and 2 Stack Phases, your DPS should have grown accustomed to their simple movement assignments. You can then ask them to attack the boss. From then on, you should frequently reach the Nuke Phase which will only take you a few attempts to overcome.