Assembly of Iron Encounter Guide: Strategy, Abilities, Loot

Last updated on May 02, 2023 at 12:00 by Abide 1 comment

Assembly of Iron is the fifth boss of Ulduar. Unlike most other boss encounters, this fight has three bosses instead of one. The order in which you kill these bosses determines how difficult the fight is and the gear that will drop. Do not forget to be aware of the various Raid Buffs and Debuffs as you work to optimize your Raid Composition for this encounter's mechanics!


Overview of Assembly of Iron in Wrath of the Lich King Classic

The Assembly of Iron fight, often referred to as The Iron Council, consists of three separate bosses, Runemaster Molgeim, Steelbreaker, and Stormcaller Brundir. These bosses can be tackled in any order, offering unique challenges and abilities depending on the order they are killed. Whenever one of the bosses dies, the others will heal to full, making AoEing them down not an option. Killing Steelbreaker last is considered the hard mode for this fight while killing him first is the easiest way to complete this encounter normally. This hard mode fight is where the quest chain begins to gain access to Algalon.


Role-Specific Tips for Assembly of Iron


DPS Tips

  • Staying inside the Rune of Power IconRune of Power as much as possible on this fight is required to make the DPS checks. Always be aware of your positioning and when you may need to move.
  • Lightning Whirl IconLightning Whirl must be interrupted as soon as possible to prevent it from dealing massive damage. Be aware of the timer at all times.
  • Shield of Runes IconShield of Runes must be removed instantly, ideally with a Mage@ Spellsteal IconSpellstealing it.
  • You will want to save your cooldowns for the third and final boss, as this is when the real DPS race starts, especially if doing the hard mode.

Healer Tips

  • Runemaster Molgeim will start to spawn Rune of Death IconRune of Death if not killed first, which spawn under random players' feet. Avoid standing with the DPS to give a chance not to spawn this on top of the Rune of Power IconRune of Power.
  • Coordinating defensive cooldowns with the tank is important when only one boss is remaining, especially if doing hard mode by killing Steelbreaker last.
  • When attempting hard mode, you will likely keep Runemaster Molgeim alive till he spawns a fresh Rune of Power IconRune of Power. This is a great time to apply some DoT to Steelbreaker in preparation for the upcoming DPS race.
  • Be mindful of the Fusion Punch IconFusion Punch timer and instantly dispel the applied magical debuff.

Tank Tips

  • Positioning the directly next to Rune of Power IconRune of Power, not inside of it, is crucial to meet the DPS requirements of the fight. You must drag the bosses out of the rune instantly, or you can die easily.
  • Remember that Stormcaller Brundir can be interrupted and stunned; a tank with the ability to do both can mitigate tons of damage this way.
  • No matter which order you choose to kill the bosses in, you will need to coordinate your defensive cooldowns with the raid when tanking the final boss, as the Supercharge IconSupercharge will boost their damage output greatly. This is especially important if doing hard mode with Steelbreaker alive last as he will also have Electrical Charge IconElectrical Charge, further increasing his damage done.
  • When attempting hard mode, tank deaths are unavoidable. Be sure to coordinate battle resses and other in-combat revivals to keep the tanks in the fight.

Assembly of Iron Encounter Abilities


Runemaster Molgeim Abilities


Steelbreaker Abilities


Stormcaller Brundir Abilities


Strategy for Assembly of Iron

As this fight has three bosses with unique abilities, the order in which you kill them determines the difficulty and, thus, the loot rewards from this fight. This means there are six different kill orders you follow here. Still, only two are recommended for the normal version and the hard mode.

Steelbreaker is the most threatening boss in this fight, and killing him last is the full hard mode version of the fight, rewarding the highest loot possible. If going for the normal version of the fight, you will want to kill Steelbreaker first to make the encounter much easier.

Runemaster Molgeim will be the second kill target in this fight for both normal and hard mode. He will periodically drop Rune of Power IconRune of Power on the floor, buffing the damage of anyone inside of the rune, including both players and the bosses. Drag the bosses out of this rune instantly to prevent them from killing your tanks, but keep them close enough that your DPS can maintain this buff and still reach the boss with their attacks.

Stormcaller Brundir is the third boss in this encounter. For the the normal version of this fight, you will want to kill him last as he is the least threatening all three bosses. For the hard mode version, you will be killing Stormcaller Brundir first, as you need the Rune of Power IconRune of Power buff as from Runemaster Molgeim as long as possible to meet the DPS requirements.


Strategy for Normal Version of the Assembly of Iron

In this strategy, your kill order will be Steelbreaker first, followed by Runemaster Molgeim, and lastly, Stormcaller Brundir will be the final boss you kill. Start by having one tank pick up Steelbreaker and the other tank pick up both Runemaster Molgeim and Stormcaller Brundir. Stack all three together and have your DPS begin damaging Steelbreaker. Remember that when one boss dies, the others heal to full, making cleave and AoE attacks pointless and a waste of damage.

The main reason for stacking the bosses together is the Rune of Power IconRune of Power that Runemaster Molgeim spawn periodically throughout the fight. These are crucial for meeting the DPS requirements of the fight and should be played around extensively. Whenever Runemaster Molgeim drops a Rune of Power IconRune of Power, the tanks must make sure the bosses are not inside of it as it will also increase their damage dealt. Make sure the melee DPS are still able to get this buff while being able to reach the boss.

Steelbreaker only has two abilities at this point in the fight, High Voltage IconHigh Voltage and Fusion Punch IconFusion Punch. High Voltage IconHigh Voltage is simply unavoidable raid-wide AoE damage every 3 seconds while Fusion Punch IconFusion Punch is a dangerous tank-nuke ability. Fusion Punch IconFusion Punch It also leaves a deadly Nature damage debuff on the target over time, which must be dispelled instantly before it deals damage. With this strategy, you are killing Steelbreaker first, so these are the only two abilities of his you will need to deal with.

Runemaster Molgeim starts off with only Rune of Power IconRune of Power and Shield of Runes IconShield of Runes. Positioning the entire raid and the bosses around the Rune of Power IconRune of Power locations are a vital part of this fight. Be sure your melee DPS can get this buff and still reach the bosses while being sure none of them are buffed with it simultaneously. Make sure to dispel or Spellsteal IconSpellsteal the Shield of Runes IconShield of Runes off of Runemaster Molgeim quickly to prevent him from gaining a 50% increased damage buff.

Once Steelbreaker dies, both other bosses will heal to full and gain a stack of Supercharge IconSupercharge, increasing their damage done and granting them new abilities. Runemaster Molgeim will now cast Rune of Death IconRune of Death under a random players feet, dealing 7,000 Shadow damage per second to all nearby players. To prevent this from being placed on top of the needed Rune of Power IconRune of Power, be mindful of the timer for Rune of Death IconRune of Death and have everyone spread out a few seconds before this spell goes off, then quickly stack back inside of the previous Rune of Power IconRune of Power. Healers can and should spread around the room after the initial Rune of Power IconRune of Power spawns, as they do not need the damage buff, allowing them to move much less often. Depending on your timing, you may wish to keep Runemaster Molgeim alive until he casts a fresh Rune of Power IconRune of Power so you can maintain the increased damage buff for the harder part of the fight.

The third boss you will be killing with this strategy is Stormcaller Brundir. Brundir starts the fight off with only Chain Lightning IconChain Lightning and Supercharge IconSupercharge. Brundir himself can be interrupted and even stunned. He should be as often as possible to prevent as much Chain Lightning IconChain Lightning damage as possible, especially on tanks. However, Overload IconOverload can not be interrupted; instead, the raid must move over 20 yards away from the boss to avoid its damage and stun.

Once Steelbreaker dies, Stormcaller Brundir will gain the Lightning Whirl IconLightning Whirl ability, dealing serious AoE damage to all nearby enemies. Luckily this can also be interrupted with a kick or stun, similar to the Chain Lightning IconChain Lightning casts. This ability must always be interrupted instantly, be mindful of its timer, and if you need to let a couple of Chain Lightning IconChain Lightning casts go through to save your kicks or stuns, do so.

Finally, when both Steelbreaker and Runemaster Molgeim are dead, Stormcaller Brundir will gain an additional ability, Lightning Tendrils IconLightning Tendrils. This spell deals serious Nature damage every second to all nearby enemies. Brundir will then "target" a player and chase them slowly, requiring that player to kite the boss and everyone else to move out of their path and away from the boss. Repeat this process till Brundir ends his cast and lands again, allowing you to continue to DPS him till he dies.


Strategy for Hardmode Version of the Assembly of Iron

The hard mode version of this fight is essentially the reversed order of the normal version. You will start by killing Stormcaller Brundir, followed by Runemaster Molgeim second still, and lastly Steelbreaker will be the third and final kill target of the fight.

Killing Stormcaller Brundir first means you will only need to deal with his Chain Lightning IconChain Lightning and Overload IconOverload abilities. Interrupt Chain Lightning IconChain Lightning as much as possible and run away from Brundir whenever he casts Overload IconOverload.

Runemaster Molgeim will function the same way he does in both the normal and hard modes. Be sure to keep the bosses near the Rune of Power IconRune of Power on the ground to benefit from the damage buff while ensuring the bosses are not gaining this buff. Run away from the Rune of Power IconRune of Power shortly before Rune of Death IconRune of Death is cast to prevent the 2 from stacking and removing your access to the damage buff from Rune of Power IconRune of Power. It is highly recommended to keep Runemaster Molgeim alive at deficient health until he casts a new Rune of Power IconRune of Power as you can use this damage increase for the final phase of the fight.

Steelbreaker is the main difference with this strategy. In the normal version, he is killed first as he is the most dangerous if left alive, which is exactly what the hard mode requires. When Stormcaller Brundir dies, Steelbreaker will gain the Static Disruption IconStatic Disruption spell. This will damage the furthest target away from him and any nearby allies, increasing their Nature damage taken by 75%.

Seeing as your healers are already spread out for the Rune of Death IconRune of Death, you can further use this to guarantee the Static Disruption IconStatic Disruption targets them. Make sure your ranged DPS are stacked inside the Rune of Power IconRune of Power and that your healers are the furthest players away from Steelbreaker. Static Disruption IconStatic Disruption will target a healer every time, allowing your DPS to continue damaging while standing together inside the Rune of Power IconRune of Power. Static Disruption IconStatic Disruption can not target the same player multiple times in a row if other targets are available without the debuff. Be sure your healers are spread out properly for this.

When both Stormcaller Brundir and Runemaster Molgeim are dead, Steelbreaker gains two more abilities. Firstly, whenever any player dies during the fight, Steelbreaker will gain a stack of Electrical Charge IconElectrical Charge, further increasing his damage output by 25% per stack. In addition, whenever a player dies, Steelbreaker will heal for 40% of his maximum health. This heal can and must be reduced by healing reduction spells such as Mortal Strike IconMortal Strike or Wound Poison Icon Wound Poison.

The second ability Steelbreaker gains is Overwhelming Power IconOverwhelming Power. This will be applied to the current tank, increasing the damage dealt by 200%. However, after 25 seconds, they will Meltdown IconMeltdown, exploding for lethal Nature damage to all nearby allies. To prevent this from wiping the raid, you will need to tank swap and have the tank with the Overwhelming Power IconOverwhelming Power debuff run out of the raid. It is worth noting that this damage can not be mitigated or prevented; it will always deal maximum damage to ALL nearby allies. Tank deaths to this mechanic are unavoidable and are considered the soft-enrage mechanic of the fight as Steelbreaker will gain a stack of Electrical Charge IconElectrical Charge every time a player dies, further increasing his damage by 25% per stack. Tanks must be ressed in combat via things such as Soulstone IconSoulstone or Rebirth IconRebirth and fully rebuffed so they can return to their tanking jobs.

Keep in mind with both other bosses dead, Steelbreaker will also have 2 stacks of Supercharge IconSupercharge, granting him 50% more damage on top of the stacks of Electrical Charge IconElectrical Charge he gains with each player's death. This makes even his basic attacks deadly the further you get into the fight, and his Fusion Punch IconFusion Punch now becomes a massive threat that requires a major defensive cooldown on the tank to survive the cast. Coordinate your cooldowns so there is always something available for each cast. Eventually, this will start to one-shot your tanks even through cooldowns as Steelbreaker will have highly increased damage through Supercharge IconSupercharge and Electrical Charge IconElectrical Charge. This is the soft-enrage timer, wiping your raid after about four casts of Overwhelming Power IconOverwhelming Power.

Mastering this fight and saving as many offensive and defensive cooldowns for this final phase with just Steelbreaker alive is crucial to defeating this hard mode encounter. Use all major offensive cooldowns together with the freshly spawned Rune of Power IconRune of Power to burn down Steelbreaker as quickly as possible and collect your extra rewards.


Assembly of Iron Loot


Assembly of Iron 10 Player Normal Loot

Item Type/Slot
Circlet of True Sight Icon Circlet of True Sight Mail Head
Cloak of the Iron Council Icon Cloak of the Iron Council Leather Shoulder
Runetouch Wristwraps Icon Runetouch Wristwraps Cloth Wrist
Belt of the Iron Servant Icon Belt of the Iron Servant Mail Waist
Leggings of Swift Reflexes Icon Leggings of Swift Reflexes Leather Legs
Boots of the Petrified Forest Icon Boots of the Petrified Forest Leather Feet
Greaves of Iron Intensity Icon Greaves of Iron Intensity Plate Feet
Stormtip Icon Stormtip Main Hand Dagger
Rune-Etched Nightblade Icon Rune-Etched Nightblade One Hand Sword
Lady Maye's Sapphire Ring Icon Lady Maye's Sapphire Ring Finger

Assembly of Iron 10 Player Hardmode Loot

Item Type/Slot
Watchful Eye of Fate Icon Watchful Eye of Fate Necklace
Belt of the Crystal Tree Icon Belt of the Crystal Tree Leather Waist
The Masticator Icon The Masticator Main Hand Fist
Perilous Bite Icon Perilous Bite One Hand Dagger
Loop of the Agile Icon Loop of the Agile Finger

Assembly of Iron 25 Player Normal Loot

Item Type/Slot
Ancient Iron Heaume Icon Ancient Iron Heaume Plate Helm
Insurmountable Fervor Icon Insurmountable Fervor Necklace
Unblinking Eye Icon Unblinking Eye Necklace
Iron-studded Mantle Icon Iron-studded Mantle Mail Shoulder
Drape of the Lithe Icon Drape of the Lithe Back
Raiments of the Iron Council Icon Raiments of the Iron Council Cloth Chest
Phaelia's Vestments of the Sprouting Seed Icon Phaelia's Vestments of the Sprouting Seed Leather Chest
Steelbreaker's Embrace Icon Steelbreaker's Embrace Plate Chest
Runeshaper's Gloves Icon Runeshaper's Gloves Mail Hands
Handguards of the Enclave Icon Handguards of the Enclave Plate Hands
Overload Legwraps Icon Overload Legwraps Cloth Legs
Runed Ironhide Boots Icon Runed Ironhide Boots Leather Feet
Radiant Seal Icon Radiant Seal Finger
Rapture IconRapture Staff
Stormrune Edge Icon Stormrune Edge Two Hand Sword

Assembly of Iron 25 Player Hardmode Loot

Item Type/Slot
Sapphire Amulet of Renewal Icon Sapphire Amulet of Renewal Necklace
Shoulderpads of the Intruder Icon Shoulderpads of the Intruder Leather Shoulder
Drape of Mortal Downfall Icon Drape of Mortal Downfall Back
Belt of Colossal Rage Icon Belt of Colossal Rage Plate Waist
Greaves of Swift Vengeance Icon Greaves of Swift Vengeance Mail Feet
Fang of Oblivion Icon Fang of Oblivion One Hand Dagger

Further Reading

Assembly of Iron is just one of the 14 encounters present in the Ulduar raid of Wrath of the Lich King Classic. If you would like to learn more about the other fights and their respective loot, please see our Ulduar Raid Hub page below.



  • 18 Jan. 2023: Page added.
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