Phase 1: First boss

All three pull simultaneously. Off tank the two smaller dwarves while the raid burns down Steelbreaker (this is the easiest kill order.)

When a Rune of Power is convenient, the ranged should stand in it (it's too risky to get Steelbreaker close to it.) If you tank Steelbreaker and Runemaster close to each other, it increases the chances of "convenient" Runes of Power for the raid.

Steelbreaker's Fusion Punch hits very hard on your tank. You can use cooldowns to mitigate it, but they're not absolutely required until phase 3 on hard mode. That said, a DK tank is far easier on Steelbreaker.

The most critical thing to surviving this fight and Fusion Punch is to make sure your healers know that the DoT it applies to the tank is dispellable and absolutely must be dispelled immediately.

A warrior is ideally suited for offtanking Stormcaller, because he needs to be interrupted each time you move him. Ideally he is tanked at least 30' from the raid so the DPS doesn't need to interrupt during Overload.

Phase 2: Second boss

Refer to the abilities to learn what each dwarf can add.

It's easier to kill the medium-sized dwarf second, Runemaster Moldeim.

In this phase, the tanks of the two dwarves need to be still tanked 30' apart ideally. The tanks swap locations in the room, moving their mobs with them, each time a Rune of Power goes down on Stormcaller, so the raid can gain the DPS increase.

Runemaster hits low enough that he can just be tanked in the Rune of Power to make sure the melee gain the full benefit also.

The Rune of Death is especially nasty: without runspeed it can be hard to get out of the area without taking a full 20-30k of damage (10000 damage per second starting immediately when it hits the ground.) He casts it on a target player, so it's helpful for someone to call out on vent when it'll end up in the ranged clump versus the melee clump versus the tank on Stormcaller.

The tank or melee must interrupt the Lightning Whirl from Stormcaller. Note that if he's in a Rune of Death a warrior will not be able to reach him. Your DK's need to be alert to assist in those cases, or other ranged interrupts need to be utilised.

Phase 3: Third boss

Easiest: Stormcaller

The easiest dwarf to have alive at this point is Stormcaller.

His additional ability sends him up in the air where he chases after raid members, pelting the raid who are near by with AE lightning bolts.

The raid must run away, minimizing damage, unless his target is someone like a tank who can take the damage: they can stand still and allow the rest of the raid to run away.

When he lands, dps him as much as possible before he takes off again

Middle: Runemaster

His dangerous additional ability is that he casts Rune of Summoning in a random location near him. He does target someone while casting it, but after watching our kill video closely I can state with certainty that it doesn't appear under their feet, and sometimes doesn't even appear in the direction he's facing. His target/direction does however seem to indicate where it will appear, especially when he's not targeting a melee.

Shortly after it's created, Elementals start pouring from it, spreading rapidly in all directions, with a vicious lightning attack.

The best way to handle these is for all ranged AE to start looking around the minute his Rune of Summoning cast is done and find the Summoning circle (it looks like the purple-style void zones like the ones from the Negaton Warp Masters in The Arcatraz.

The elementals are snarable (e.g. improved Blizzard) and tauntable.

He's still casting Rune of Death and Rune of Power.

Remember that Rune of Death is targeted on a raid member, and he changes targets, so it's possible to react very quickly.