When you hear folks refer to the Iron Council, they're actually talking what the game itself calls the Assembly of Iron. The three members of the Assembly of Iron are Steelbreaker, Runemaster Molgeim, and Stormcaller Brundir.

In my raid, we're creative and call Steelbreaker the "Big One," Molgeim the "Medium One," and Brundir the "Little One." It took many nights for us to come up with that, I promise.

There's a lot of variety to how you can do this fight. You are generally going to kill all three in order, after all. Hard Mode for this fight is activated by killing Steelbreaker last. Why?

The basics of this fight is that each three members have different powers. Killing the first of the three means the remaining iron-men will get a soft enrage, making them hit a little harder. They will also gain a special and unique power. Each member of the Assembly of Iron has different powers, obviously. Then, when you kill a second member, the last guy gets a really uber power. Steelbreaker's power is, without doubt, the most difficult to work through.

Let's introduce you to each member of the Assembly.

Steelbreaker

• Steelbreaker will "white damage" punch a raid member for about 20k damage on Heroic, and about 10k damage in Normal.
• Fusion Punch - An attack infused with energy that inflicts huge damage to its target, as well as leaving a ticking debuff on the target. The good news is that he hits only the tank with the ability. The debuff is a magic effect and must be dispelled as quickly as possible. Be ready to do that instantly. Fusion Punch is a good place to use one of your defensive cooldowns.
• High Voltage - An aura that ticks to do damage to the entire raid. It's fairly low level damage, but you're going to want to have some raid heals ready to go.
• Static Disruption (1 Council member dead) - Inflicts serious damage to enemies in a 6 yard radius. More importantly, it also increases Nature damage taken by 75% for 20 seconds. The power seems to prefer ranged targets, but will hit anyone.
• Overwhelming Power (2 Council members dead) - Targets the current tank on Steelbreaker. Causes the affected player to deal 200% more damage, but gets Meltdown after the duration of the debuff. That means you have 60 seconds to kill Steelbreaker before your tank dies.
• Meltdown (2 Council members dead) - Occurs at the completion of the Overwhelming Power debuff. Kills the tank and causes Nature damage to any players within 15 yards. In other words, everybody dies.

Runemaster Molgeim

• Rune of Power - A ground-targeted AoE that will buff anyone standing on this rune to do more damage. While it is always summoned under one of the Iron Council, you should get your ranged folks on it as soon as possible. They get the buff.
  
• Shield of Runes - Shield absorbs up to 50,000 heroic (20,000 normal) damage. If the shield absorbs the full amount of damage possible, Molgeim gains a 50% damage increase for 15 seconds. Mages really want to spellsteal this. Barring that, just dispel it.
• Rune of Death (1 Council member dead) - 26 yard radius ground-targeted AoE which will do 3500 shadow damage per half second on Heroic or 2750 Shadow damage per half second Normal. This is essentially a void zone, which we're all pretty familiar with. Don't stand in it.
  
• Rune of Summoning (2 Council members dead) - Creates a rune of summoning which periodically spawns Lightning Elementals. He will cast it under the feet of a player in the raid. Elementals will charge toward that member, and probably explode on contact.
• Lightning Blast (2 Council members dead) - When the add reaches its target it will deal a 30 yard explosion of 14138 to 15862 Nature damage on heroic or 9425 to 10575 nature damage on normal, killing the add in the process.
  

Stormcaller Brundir

• Chain Lightning - Deals medium Nature damage to its target, and then chains onto an additional target. It can hit up to five people, and will keep bouncing to anyone within 10 feet. You should spread out to avoid chaining this ability. It can be interrupted, though.
• Overload - This works just like Loken's ability. Overload is a huge point-blank explosion, and it can not be interrupted. You probably want to drop a defensive cooldown on the tank when you see it coming, but everyone can technically run away from it in time.
• Lightning Whirl (1 dead) - Deals 5655 to 6345 nature damage on heroic or 3770 to 4230 nature damage on normal per bolt. Fires multiple bolts per second and needs to be interrupted as quickly as possible.
• Lightning Tendrils (2 dead) - Brundir starts flying, shooting lightning bolts around. He'll randomly target a raid member, and fly toward that person. He does lots of damage if he catches up with the target, so it's important to kite him.

Putting it all together

Like I mentioned, the "easiest" way to kill the Assembly of Iron is to kill Steelbreaker first. (Hard Mode, after all, is simply killing him last.)

Have your tanks separate the Assembly of Iron. If you have three tanks available, using one tank per Iron Council member is best. However, you can have one tank (on Normal) handle both Runemaster and Stormcaller. Your other tank will be on Steelbreaker. Since Steelbreaker has a limited-range area effect aura, you want to kite him away from the tank and healer who's handling Runemaster and Stormcaller.

Kill Steelbreak first. Be prepared to counter Fusion Punch with defensive cooldowns. Other than Fusion Punch, Steelbreaker's incredible damage, and interference from the other two iron-men, it's a basic tank and spank. Again, be very careful to get your ranged on top of any Rune of Power, since it'll buff their damage and speed you along. If your Mages can steal some Runes of Power from Runemaster along the way, so much the better.

Kill Runemaster next. At this point, have the tank who was on Steelbreaker peel Stormcaller away. Watch out for Runemaster's new Rune of Death ability, but hopefully everyone is well trained to not-stand-in-stuff. This part really shouldn't take long, but your mileage may vary. (If you lost folks while killing Steelbreaker, for example, you might be a little low on DPS.)

Lastly, kill Brundir. This is so much about interrupting and kiting that, if you have those two skills down, you really won't have much trouble. The hardest part is behind you, really.

Once you've downed the Assembly of Iron, then it's time to move on to Auriaya.