M'uru (tactics)

As of patch 2.4, M'uru is missing from his location beneath the Blood Knight headquarters in Silvermoon's Farstriders' Square, having been captured by Kael'thas and brought to the Sunwell Plateau. Magister Astalor Bloodsworn curses Kael'thas and his felbloods for their treachery, commenting that Lady Liadrin is looking for another source to power the Blood Knights' magic.

M'uru is located behind Rohendor, the Second Gate and ahead of Archonisus, the Final Gate, placing it as the fifth boss encounter of the instance. M'uru was made accessible at the same time across all servers five weeks (29 April 2008) after the opening of Rohendor, the Second Gate. The removed quest Rohendor, the Second Gate warns that M'uru is now a "twisted reflection of its former self".

M'uru

 * Negative Energy: A black beam used on 4-5 random targets every second throughout the fight. This does ~940-1060 unresistible Shadow damage.


 * Summons 2 Shadowsword Berserker: Run very fast, can be crowd controlled. Dual Wielders, hit for 3.5k with Main Hand, 1.5 with Off Hand. Has buff called Flurry in which attack speed increased is by 100%, movement speed increased is by 100% for 6 sec. 124k HP.


 * Summons 1 Shadowsword Fury Mage: Run very fast, can be crowd controlled. Fel Fireball (2 sec cast) deals 4250 to 5750 fire damage (resistible.) Also melees for 3-4k damage. Has a buff called Spell Fury which can be spell stolen. Spell Fury causes spells cast to be instant, increase magic damage by 50% and make them unable to move. 104k HP.

These spawn 1 Mage and 2 Berserkers at both sides every 60 seconds. That is 6 Humanoid adds every minute. The Humanoid adds spawn from the corridor behind M'uru, and the ramp/doorway from which you enter, running towards the center.

Void Spawns and Void Sentinel can be snared, Void Spawns can be feared.
 * Summon Void Sentinel: Summons a large Voidwalker that hits very hard, roughly 8-10k melee on tanks (~25k unmitigated). 70k HP.
 * Shadow Pulse: AoE ability which deals about 4k shadow damage about every 3 sec.
 * Void Blast: Single target attack which deals 10-11k dmg and puts a debuff slowing your attack by 35% (is spell reflectable and can be resisted).
 * 8 Void Spawns appear upon a Void Sentinels death, doing 700-900 melee damage each. 30k HP. Can be enslaved by warlocks, can be worthwhile enslaving a few at the end of phase one to use against Entropius or even during phase 1.
 * Shadow Bolt Volley: 1200-1600 shadow damage to targets around them (resistible.)


 * Darkness: Every 45 sec, creates a large Void Zone, covering the larger circle (i.e. from up to the outside edge of the wide purple band in the center) in the middle of the room, and does ~3,000 shadow damage per second to anyone standing in it and they cannot be healed. This also spawns 8 Dark Fiends which explode for 5,000 raid-wide damage and leaves a 2000 damage dot on raid when one reaches a target (resistible). These can be killed by Dispels or Purges.


 * Enrage: M'uru and Entropius share a 10 minute enrage timer. At this point all damage increases by 5x and the raid instantly wipes due to 2500 - 10,000 damage Negative Energy attacks.

Entropius

 * Negative Energy: Becomes a Chain Lightning type attack with random targets every second throughout the fight. This does ~1885 to 2115 Shadow damage to the 1st target, ~50% of that to 2nd target and ~25% to 3rd target. The number of primary targets increases every 12–13 seconds. Unresistible.


 * Darkness: Spawns a Void Zone under a player dealing 3000 Shadow damage every second. Will spawn 1 Dark Fiend after a few seconds which must be Dispelled or Purge.


 * Singularity: Spawns over a player. After a few seconds will move around and toss any nearby players around dealing 500 damage a tick.

Raid Composition
M'uru is a very DPS intensive fight, and as such it requires stretching your healing and tanking as much as possible. This includes having about 4 tanks, 6 healers and 15 DPS. It is highly recommended, if not absolutely necessary, to include a Protection Paladin as one of your tanks to pick up the Void Spawns that spawn.

You must divide your DPS up into a few sub-groups, that are able to each put out substantial amounts of DPS. Generally you will have 2 groups assigned to killing Humanoid adds, as well as a Warlock group assigned to kill Void Sentinels and Void Spawns.

Pulling M'uru
When you are ready to pull M'uru, DPS will mount up in the door way and be ready to run in to their positions and burn M'uru as hard as possible before switching to your respective jobs. Humanoid tanks should be ready to pick up their adds on each side from the start, using only one or two attacks to throw up a Sunder Armor or Faerie Fire on the boss.

Can also use an Eye of Kilrog to engage and quickly reset him, allowing 30 seconds for the raid to setup and position themselves.

Phase 1
While your raid group runs in and attacks M'uru, you will be in Phase 1. This phase is a combination of a control fight and a DPS race. Each Humanoid group, which will be comprised of one tank, one healer, and three to four DPS, will be in charge of controlling each add entrance (the doorway and the opposite side of the room, where the ramp down to Kil'jaeden is blocked off.) A Mage is also highly recommended on each side, to Polymorph a Berserker or Mage. You will also have a group of AoE, generally Warlocks, to control the Void Sentinels and Spawns. This AoE group is recommended to be comprised of a Protection Warrior or Feral Druid, a Protection Paladin, 3-4 Warlocks and 2 healers (one for each tank). You should also have two raid healers assigned to keep the rest of the raid up.

Humanoid Adds
Each Humanoid Wave consists of two Berserkers and one Mage. When the Humanoid wave enters the room, the tank should pick up all 3 of them while a mage sheeps a Berserker and the tank drags the other two adds slightly away from the sheep so multitarget attacks such as Blade Flurry, Cleave, Sweeping Strikes or Multi-Shot can occur.

Void Sentinels and Void Spawns
The warrior will need to be fast in picking up the Void Sentinels, and the warlocks need to be quick in DPSing the Void Sentinels to allow this mobility. Warlocks will have to manage a rotation on the Sentinels and Spawns to ensure that DPS is still active on M'uru, you need to allow the Protection Paladin to gather up two or three sets of spawns before AoEing them down. Warlocks should DPS the Void Sentinels, kill them, allow the Protection Paladin to pick up the adds and while this is occurring DPS M'uru until another Sentinel is ready to be DPSed.

Darkness
You should assign a Shadow Priest to DPS M'uru full time and Mass Dispel the Dark Fiends when Darkness comes up inside of it, thereby killing them. Be ready to target ones that resist with a single Dispel or call it out so someone else can Dispel/Purge.

Phase 2
After M'uru has been slain, he transforms into Entropius, a demon-type void god. Most of the adds that were alive during the transition should be dead or almost dead as there is 10 seconds before Entropius engages the raid. Entropius has 1,450,000 health and at this point the fight turns into an all-out DPS race before the raid damage from Negative Energy ramps up substantially and overwhelms your healers. This fight also tests the reflexes of all players in the raid and their ability to move on a seconds notice.

At level 80
At level 80, like Brutallus before him, M'uru is a trivial encounter due to the fact it was designed to be a gear check and dps race. However, please remember:
 * At least 2 tanks should still be assigned to pick up any adds that are summoned and/or spawned around the encounter area (especially Void Sentinels).
 * Stay out of void zones.
 * Spellsteal / purge / (mass) dispell Dark Fiends.

Loot
M'uru drops 3 items plus one of the Sin'dorei rings.