Skip to main content

Assembly of Iron, Healer Guide

Updated 1 month, 3 weeks ago for patch 3.4.1 by Preston. View the change log.

Assembly of Iron Dungeon Journal ModelThis page covers a healer-focused strategy for Assembly of Iron in Ulduar in Wrath of the Lich King. While it's tailored for healers, other roles may also find the information useful. If you have any suggestions or feedback, you can leave a comment below or tweet @PrestonDvorak.

This guide has been updated and maintained based on my own experiences with the encounter, combat log information, and Dungeon Journal information. I'll continue to update it as-needed.

Assembly of Iron ModelGeneral Mechanics and Abilities

During this encounter, players fight against all three members of the Assembly at once.

  • Shared Abilities
    • When a boss is killed, the remaining bosses gain a stack of Supercharge, increasing damage dealt and granting new abilities, detailed below.
  • Steelbreaker
    • The tanks will be dealing with extra moderate damage from Fusion Punch (dispel, magic), and extra moderate damage over time if the effect isn't dispelled.
    • Every 90-seconds, deals light damage over time to all players with High Voltage.
    • With 1-stack of Supercharge: stay more than 5-yards away from other players to avoid chaining the damage dealt and increased Nature damage taken effect from Static Disruption.
    • With 2-stacks of Supercharge: every 20-seconds, targets the current tank with Overwhelming Power, greatly increasing damage dealt, but killing them and any players within 15-yards when the effect expires.
  • Runemaster Molgeim
    • The tanks should keep enemies out of Rune of Power to prevent them gaining the increased damage dealt effect.
      • Players should stand in the Rune of Power to increase their damage dealt.
    • Purge Shield of Runes to remove the damage absorption effect before it's depleted and grants greatly increased damage from Shield of Runes.
    • With 1-stack of Supercharge: avoid the location of Rune of Death, targeted at a random player's location. Players inside take moderate damage over time.
    • With 2-stacks of Supercharge: every 20-seconds, spawns a Rune of Summoning at a random player's location, which gradually spawns 25 (10 on 10-player) Lightning Elementals.
      • Lightning Elemental
        • Susceptible to most Snare, Stun, and crowd control effects.
        • If allowed to reach a player, deals heavy damage to all players within 30-yards with Lightning Blast.
  • Stormcaller Brundir
    • Interrupt Chain Lightning to prevent the light damage dealt to up to five players.
    • Stay more than 30-yards away to avoid Overload. Players hit take heavy damage and are Stunned.
    • With 1-stack of Supercharge: about every 15-seconds, interrupt Lightning Whirl to prevent the light damage dealt to several random players.
    • With 2-stacks of Supercharge: every 90-seconds, during Lightning Tendrils, stay more than 18-yards away to avoid the light damage over time.

Assembly of Iron ModelHardmode Differences

  • Killing Steelbreaker last is all that's needed to satisfy hardmode criteria, and means tanks will be dealing with Overwhelming Power, detailed above.


Assembly of Iron ModelHealing Notes

Quick Notes, All Difficulties

The notes below mostly pertain to progression difficulty, meaning if you out-gear the difficulty you're on or use extra healers they may not apply.

  • Use Major Cooldowns
  • Use Minor Cooldowns
  • Pre-heal Before (mainly for heal over time classes)
  • Other things to watch for
    • Healing required will get lower over the duration of the encounter if bosses are killed in this order: Steelbreaker, Runemaster Molgeim, Stormcaller Brundir.
    • Conversely, killing bosses in a hardmode order will increase healing required over the duration of the encounter: Runemaster Molgeim, Stormcaller Brundir, Steelbreaker

Assembly of Iron ModelDebuffs to Track


Buffs to Purge

Assembly of Iron ModelUseful Addons

Ulduar DBM Import Code for Healers - +

To use this import code, install the Deadly Boss Mods addon, type /dbm in your chat, expand the Wrath of the Lich King header in the left-hand panel, click on the Ulduar heading, click on the Load AddOn button in the right-hand panel if necessary, click on the Import Profile button, paste the code into the box and click Import. Note that importing this code will replace all of your current settings for all Ulduar bosses.

Comment on Assembly of Iron, Healer Guide