Guild Wars 2 – Rage Suppression

Head over to the Black Citadel and into the Imperator's Core. Head to the center of the Black Citadel and up the stairs that you find there. Just start and keep heading up. You will find the entrance to the instance at the top of the Imperator's Core. It is just to the South of the Imperator's Core Waypoint. You can skip some of the travel up by simply taking the Waypoint as soon as it becomes available to you (which is about a level or two). Once there head into the instance.

Inside the instance just go right on through the door. You will arrive in the Blood Tribune Quarters with Rytlock Brimstone, who is looking down over the Black Citadel below. He has some news he needs to pass onto you:
Hero: Good news Tribune. Soure Doomsday/Fyon the Wraith has joined my Warband.”
Rytlock Brimstone: “Well done, Legionnaire. Here's you next assignment: One of Steelbane's men, Rage Steeltongue, has become a problem. After you took over, he joined the Flame Legion. He's determined to bring you down at any cost.”
Hero: “Not a problem. We'll drag gim back to Blood by his scrawny tail.”
Rytlock: “No. There's a time for mercy, and a time for mercy-killing. I'm not giving Rage the chance to betray Blood Legion twice.”
Hero: “We'll give him a one-way trip to the Mists.”
Rytlock: “That's the plan. Meet me down by the citadel gates when you're ready to deploy. Dismissed.”

Leavign the first instance. Head on over to the entrance of the Black Citadel itself, by the Mustering Grounds Waypoint. Just head East though the Gates.On the other side of the gates you will find Rytlock waiting for you inside the next instance:
Rytlock: “At least, Legionnaire. Ready to get started?”
Hero: “More than ready, Tribune Brimstone. What's our next move?”
Rytlock: “That mongrel toady, Rage Steeltongue, was spotted in the area. Start with those cattle ranchers – find out why they're here and if they've seen anything unusual. Get moving!”
Hero: “Sir, yes sir!”

Approach and talk with Rancher Tolona Ironrustler:
Tolona: “Watch your step around my stock. They're harmless, not housebroken.”
Hero: A) “Why are the cows here?” B) Why did you bring these cow in now?”
Tolona A) “Some Legionnaire came to the ranch and order me to herd them into the citadel. And when a legionnaire orders me to herd my cattle into the citadel, I herd my cattle into the citadel.”
Hero: “Do you know which legionnaire gave the order?”
Tolona: “No. Never seen him before, and he didn't give a name. Helped with a few packs, though. Did a passable job, it sounds like he may have mixed some tools in with the feed.”

Tolona B) “This Blood Legionnaire said a Flame Legion attack was coming and that my ranch was in danger. He ordered me to heard them here, for safety.”
Hero: “What was the Legionnaire's name?”
Tolona: “he wouldn't say. He was in such a rush he even helped me with the packs. Did a passable job. But it sound of it, he may have mixed some tools in with the feed.”

Hero: “I'll need to examine those packs.
Tolona: “Sounds like everyone wants to poke around my cows today. Help yourself.”

With that conversation done, head over to the Pack Bulls and start investigating them. The two on the sides are the most likely to have a strange bundle. It will smell of gunpowder and oil that is also ticking. Shoo those pack bulls away. After the second a quick conversation will happen:
Tolona: “Hmm. You know, if I wasn't looking at a big pile of cow chucks, I'd be laughing.”
Hero: “Laugh later. Right now I need to know where those Flame Legion imposters went.”
Tolona: “They went deeper into town. You'll find them that way.”
Rytlock: “Lead the way, Legionnaire. Rage just got promoted from 'mongrel toady' to serious threat'.”

Head along the path to your left. You will find Gnarl Snagtooth down the slope in the path. There you will find out more of the Flame Legion's plan:
Gnarl: “Another inspection? Like I told the last guy – the defenses still have a way to go, but we're making progress.”
Hero: “This is no inspection. Have you seen an unfamiliar officer around?”
Gnarl: “I didn't know the legionnaire who inspected our supplies. But he knew procedure and had the right uniform. And he complimented me on my vigilance. Seemed on the level.”
Hero: “Drop that crate and step back, soldier. Right now!” or “Let me see that thing.”

The result is the same either way. The question is whether or not you get blown back in the process. A large number of Fire Imps and Embers are released from the crate. There are at least a good dozen or more that need to be killed off here. Defeat them all and then head over to the Northeast. Go on up the slope and you will find Aziel Jawbreaker:
Hero: “What happened to you, soldier?”
Aziel Jawbreaker: “It was a Blood Legionnaire. He seemed friendly, but when he clapped me on the shoulder all the strength just drained right out of me. He took my clothes, my boots, my entire kit.”
Hero: “Tell us where he went, then get yourself to the infirmary.”
Aziel: “He was headed for the Scrap yard. Give him a good thrashing for me when you find him.”

Continue on to the Northeast from here. It will not be long before you arrive at the Scarp Yard where you will find Steeltongue talking with one of the Flame Legion:
Smoke Shaman: “Did you get the gear?”
Rage: “Got it right here. Put it on and you'll have free run of the place. They won't figure out they've been infiltrated until the damage has already been done.”
Hero: “It's over, Steeltongue. I took down that coward Steelbane, and now it's your turn. Just ell me one thing: Why? Why'd you betray us and join the Flame Legion? Too proud to serve your new legionnaire?”
Rage: “I had it all set. That coward Steelbane was the only thing between me and taking over this Warband. Then you came along and beat me to it. At the end of the day, I don't care whose banner I serve under as long as I'm the one giving order. Like right now, 'boss'. I'm ordering you to die

After the conversation you have 3 Flame Legionairres to fight. One of them a Smoke Shaman. Just set into them and attack with full force. After a second wave, Rage Steeltongue will reveal himself and you can start attacking him. He cheats a bit with some teleportation. Aside from that, focus on area attacks or just decimate the ranks of the Flame Legion as best you can.

Hero: “The Flame Legion must be getting desperate if they're resorting to cow bombs.”
Rytlock: “Desperation is a weapon, Legionnaire. If they're targeting our defenses, they're planning a major assault on the city. Tactically, a night attack makes the most sense. When it comes, I need you and your Warband in the field. When the fighting starts, your orders are to maneuver behind their front line troops and take out the rear guard. Without mages and artillery to support the main force, they'll never breach the Black Citadel's walls. It's an important job. Can you handle it?”
Hero: “My soldiers are ready, sir. We won't let Blood Legion down.”
Rytlock: “Good. Dismissed.”