Murmur

Murmur is the fourth and final boss of Shadow Labyrinth, an instance wing of Auchindoun. It bears an appearance similar to Ragnaros and Thunderaan. Before Ahune's appearance, he was the only elemental with Elemental Lord status in Outland.

Murmur is an incredibly powerful elemental born when the Universe was created, about whom little is known. The Shadow Council inhabiting the Shadow Labyrinth summoned it for their nefarious purposes, but seem to be having trouble keeping him under control. Its history is briefly documented in the Codex of Blood, which reveals Murmur is the primordial essence of sound.

Attacks and abilities

 * Basic Melee: Hits for 1,600 damage on plate with 58% mitigation (approx 5,000 base). Slow attack speed.
 * Sonic Boom: Builds up (this is accompanied by the visual effect of waves of energy being drawn in, and an emote "Murmur draws energy from the air" or something similar) and then releases a sonic boom outwards hitting everyone within 34 yards (the effect extends just beyond the slightly-raised ring in which Murmur stands). It damages for 90%-95% of your current health (modified by stance multipliers) plus an additional 12% of your maximum over 6 seconds, and applies a debuff that reduces movement speed by 90%. This attack is resistible and can be avoided by spells and talents such as a Felguard's Avoidance or a druid's Predatory Instincts.
 * Murmur's Touch : Puts a debuff similar to Baron Geddon's Living Bomb ability on a random target (including the primary target). The target explodes after 14 seconds and is launched into the air. Players within 10 yards of the explosion will take ~3700 damage and are silenced for 6 seconds.  The target can use abilities such as Divine Shield and Ice Block to prevent the damage taken from the explosion, but the explosion can still hit other party members. Rogues can use Cloak of Shadows to dispel the debuff entirely; however, the explosion will still trigger, so they will need to watch out for the proximity of other players.
 * Shockwave: Murmur sometimes pulls a random player towards him and will then cast Shockwave, dealing 1100-2000 Nature damage to all enemies around him and silencing them for 6 seconds.
 * Resonance: Applies a debuff to all targets that increases Nature damage taken by an additional 2000 for each stack, while also also hitting for 2000 base Nature damage. This attack is only used when there is no target in melee range for several seconds.

Heroic
Murmur gains two additional abilities on Heroic:
 * Murmur's Touch / Shockwave - This pulls all other players to the location of the affected player, including the tank, and explodes after 7 seconds instead of 14. Players are released after being pulled together, and need to move away from the affected player as quickly as possible before shockwave explodes—usually by having the affected player move to the other side of Murmur (but still within the circle, so that Thundering Storm doesn't get them).
 * Thundering Storm - this ability—which you saw Murmur cast on Shadow Cabal members in his room—hits all players for ~2500 who are not completely inside the raised, inner ring in which Murmur is standing. It is not recommended to heal through this with only a single healer. Having ambient healing (a shadow priest and/or druid with Improved Leader of the Pack) can help with this quite a lot. Generally avoided by positioning all members inside the inner circle.

Strategy
The fight versus Murmur is relatively easy when everyone understands their role in the fight. No resistance gear is required.

Murmur starts with 40% health, which is a total of around 169k. Murmur is stuck to the place just like Ragnaros and he has an aggro range of 10-15 yards. Additionally, he uses a powerful ranged attack if there are no possible melee targets.

The main tank will run in and get aggro while the rest of the group spreads out at maximum spell/attack range to avoid extra damage from the AoE explosion from the Touch of Murmur effect.

Sonic Boom
Periodically, Murmur will pulse and emote. At this point, he will stop attacking, and the tank and any melee will need to run out of the circle around him, or they will be hit by his Sonic Boom. Warriors should Intervene to someone standing outside the ring. This will almost guarantee no damage from Sonic Boom. The tank will then need to get back in range immediately.

Alternatively, the tank can stay in and take the hit from the Sonic Boom. A large heal will need to be timed right after the hit, in order to restore his health before Murmur resumes attacking. Rogues can Cloak of Shadows through a Sonic Boom if timed correctly.

Macro - Using the following macro can be useful for warrior tanks: /rw Sonic Boom Incoming. Get out of range NOW! /target "Name of Healer/DPS" /cast Intervene

Murmur's Touch
The ranged classes will be primarily concerned with Murmur's Touch. Everyone needs to watch for this debuff and run away from his teammates to avoid damaging and silencing them. Spells such as Divine Shield will prevent damage from occurring to the person with the debuff, but the AoE effect still occurs. A common tactic to avoid the fall damage that results from being launched in the air is for the player with this debuff to run into the tent situated in the area.

If a healer receives Murmur's Touch, he should watch the countdown timer carefully and make sure the tank is healed to near-full before Murmur's Touch goes off. The explosion will interrupt the healer's spellcasting, and since he's considered to be "moving" while he's in the air, the healer won't be able to cast any healing spells other than instant-cast spells until he lands.

Heroic mode
Everyone must position themselves completely within Murmur's raised inner circle to avoid his Thundering Storm—if you're on the raised ledge or outside you will be hit by Thundering Storm.

Have all players close, on the flat ground immediately next to Murmur. When Touch of Murmur occurs, there is a large, very visible green beam and all players are drawn to the target. The person with the debuff should run through Murmur to the back, where he can detonate without hitting party members. He can then run forward and resume the fight. Alternatively, use fighting positions such that no party member is within 10 yards of any other, and everyone can simply run back to their positions when drawn to the target of the touch.

Murmur is surrounded by a raised ring. Stay completely inside the ring—not on the inner slope, but on the flat part of the floor—to avoid Thundering Storm. When Murmur starts casting Sonic Boom, run across the raised ring to get completely outside of it. When he finishes casting it, run back inside of the ring. The raised ring itself, including both slopes, is a death zone—characters standing on it get hit by both Sonic Boom and Thundering Storm. The Sonic Boom has a snare component, so victims take a long time to get back inside of the dark ring, take multiple Thundering Storm hits, and die. Run out and in quickly!

Murmur is very unforgiving about not being tanked in heroic mode; he will start using Resonance almost immediately. Even a tank charging back may not prevent a single application of it. He will also fire off a Thundering Storm immediately after Sonic Boom.

A priest healer is capable of healing through the sonic boom with little trouble. When you see Murmur casting Sonic Boom, immediately place a shield and Prayer of Mending on the tank. Time a Prayer of Healing to land immediately after the Sonic Boom. Follow through with a second Prayer of Healing and 2 Circle of Healing if you have it. If Circle of Healing is not available any other healing spell can be used. This allows the entire group to stay put through the Sonic Boom.

Additional notes

 * A rogue can make an excellent tank when Murmur does his Sonic Boom. Combine Cloak of Shadows with Evasion or Ghostly Strike, so that while the tank is leaving the AoE, melee aggro is maintained.
 * A Mage can Ice Block when Murmurs Touch is applied to someone. This way he won't get pulled through the air and can maintain his DPS.
 * A Shaman's Earth Elemental is immune to nature damage, so it can tank Murmur through a sonic boom (and thus help avoid resonance). The elemental dies fast from his melee damage, so the main tank still needs to be back ASAP.
 * Nature Protection Potions can be helpful with this encounter.
 * Murmur's magical attacks are not mitigated by Nature Resistance, yet immunity of the Earth elemental does work (non-heroic tested only)
 * In case of an emergency, a priests Shadowfiend can take a few hits before dying. This is useful if the tank got hit by sonic boom, as the healer can heal him while maintaining melee aggro.
 * A holy priest can drop a Lightwell outside of Murmur's circle to allow ranged DPS to heal from attacks such as Murmur's Touch without having to turn his attention from the tank—since there is a lack of adds or constant DPS outside of his circle, the HoT can run for its full span without being interrupted. This has not been tested in heroic.
 * Murmur does not attack while he is charging up his Sonic Boom attack.
 * Using some kind of casting bar mod to display Sonic Boom can be very helpful for melee characters.
 * Murmur will occasionally pull a ranged player towards him. This will not occur during Sonic Boom charging. The pull does not cause damage, but the character will receive fall damage.  Mages can blink out of this when dropping down again to avoid fall damage.
 * The Arcane Container for the quest Entry Into Karazhan is on the left-hand side, facing Murmur, and can be reached without aggroing him. This, however, spawns a 70 elite Guardian from the container, meaning you will have to carefully watch your range as to not accidentally aggro Murmur at the same time. The guardian will drop the First Key Fragment for the quest once killed.
 * He is susceptible to Deadly Poison and therefore, Envenom.
 * A paladin tank can put on Divine Shield right before Sonic Boom and keep tanking with the shield on without losing aggro
 * Murmur as of 2.4 can be hit by bleed effects, like Rupture.
 * Murmur will trigger hunter traps. He is fixed in place so the trap must be placed directly on top of him.  This is not recommended for non-heroic.
 * For ranged DPS, you can hide behind the wooden pillars (placing it between you and Murmur) and you will not get pulled and will not receive any fall damage. This can only be done in non-heroic.
 * His weapon seems to be a just like Ragnaros', Thunderaan's  and Ahune's.

Trivia
Although in the Codex of Blood says a single whisper would destroy a world, you can hear Murmur's sounds as you fight him.

Quests

 * Must be completed in heroic mode.
 * Must be completed in heroic mode.
 * Must be completed in heroic mode.