The southern quarter of the Iron Citadel was the quarter that the Iron Citadel's administrative class had stopped describing as part of the Iron Citadel.
Not officially. The district was on every map, the addresses in the registry, the tax records maintained. But the quality of the infrastructure relative to the northern districts where the mining sector's management lived, the specific distribution of maintenance attention relative to the population density — these told you what the administrative priorities were more accurately than any official document.
He read the southern quarter through the Fate's Eye as he walked its main corridor.
The corruption density was higher here than the northern commercial district. He had read nineteen corrupted practitioners in the northern areas. In three blocks of the southern quarter, he had read thirty-four. The distribution was still not purely demographic in the way a water-supply contamination would be — it was varied by individual, with the majority of the population uncorrupted — but the concentration differential was too large to be coincidental.
He followed the density gradient north.
Density gradients pointed back to sources. The higher the concentration, the closer to the origin point of whatever was introducing the corrupted mana. He walked the gradient for four blocks until it began to drop off on the far side of a large courtyard-facing building that the spatial sense read as a significant mana-output structure — not a dungeon, not a portal; something constructed, running continuously, producing the specific frequency of output that his comprehension was building a model of.
The building's public-facing aspect was a tavern.
He went inside.
The establishment was the kind that frontier cities produced when populations needed somewhere to go that was warm and offered food and drink and required no particular social standing to enter. The customers were the cross-section of the southern quarter's working population — mine workers, craftsmen, small-scale merchants, a few practitioners who registered as low Tier 2.
He took a table at the room's far edge, the position that gave him a clear line on both the main entrance and the back corridor without placing him in the natural flow between them.
The menu was handwritten on a board above the bar. He ordered what looked like the establishment's version of a northern stew — game meat, root vegetables, the bone-stock base that the northern cooking had been doing well in his experience — and a pot of tea, because the ambient temperature had been working through the crawler's insulation for five days and the interior of the building, despite being considerably warmer than the street, was still a full twenty degrees below what his body considered comfortable.
He ate and read the room.
The corruption in the people around him was present at the specific staging level he had been seeing throughout the southern quarter — recent exposure, within the past two weeks, the formation in early integration rather than the deep structural involvement he had seen in Saylor after two years. The contamination vector was working through the population recently and continuously.
The kitchen, through the back corridor — the spatial sense registered something that did not belong in a kitchen. The mana output that the building was producing came from that direction. Not a formation he recognised; something he was going to need to get closer to in order to properly characterise.
He ate the stew, which was as good as the northern cooking had been training him to expect, and thought about the best way to access a building's back areas without it being a diplomatic incident this early in the mission.
His watch chimed.
He checked it under the table.
Rosalind's communication link — Valerian's office routing through her channel, which was what happened when the Emperor needed to reach him quickly and the standard communication went through the established contact point.
He stepped outside into the cold, found a building shadow that gave him the acoustic privacy the conversation needed, and accepted the connection.
"What I'm about to tell you is going to re-frame what you're seeing in the Citadel," Valerian said, without the standard greeting formalities. He used that register when the situation required directness more than protocol.
"The corruption in the southern quarter," Markus said. "You have intelligence on the source."
A brief pause. "You've already found it."
"I've found the distribution pattern. Not the source yet." He kept his eyes on the building's exterior. "Tell me what you know."
Valerian's briefing was specific and came from the intelligence apparatus rather than from the diplomatic channel: the faction within the Dominion's administrative structure that had been systematically undermining the trade relationship negotiations for two years. Not an external saboteur. An internal one — the specific fraction of the Dominion's mining sector management that had calculated that maintaining scarcity was more profitable than establishing reliable trade routes.
The corruption wasn't ideological. It was economic. The southern quarter's population was being deliberately corrupted through a contaminated mana-supply network that the faction controlled, and the specific behavioural amplification the corruption produced — amplifying existing tendencies toward resentment and territorial defensiveness — was producing the social conditions that kept the southern quarter's workforce hostile to any engagement with foreign trade entities.
Trade treaty negotiations failed when the general population was hostile to them. The faction had found a way to manufacture that hostility reliably.
"The Dominion's administration is either complicit or unaware," Markus said.
"Divided," Valerian said. "There are factions within the Dominion's leadership that want the trade relationship and are being systematically undermined by this. Finding the source and addressing it is going to be necessary before any formal negotiation can produce binding results."
"I understand," Markus said. "Give me forty-eight hours."
"You have forty-eight hours," Valerian said. "After that, the formal diplomatic channel opens and whatever I know, the other side knows we know, which changes the negotiation dynamics significantly."
The connection closed.
He stood in the cold for a moment and revised his operational picture.
He went back into the tavern, paid for the meal, and left through the front door with the specific purposefulness of someone who has determined that the back door is not the right approach to this particular building on this particular evening.
Sven found him rather than the other way around.
Which was, he noted, information in itself.
The man had been sitting three tables away in the tavern throughout the meal, drinking slowly and watching the room with the quality of attention that either meant he was also running some kind of intelligence operation in this space, or he worked for someone who had been anticipating a foreign arrival with Fate's Eye-level perception and had stationed someone to watch for exactly that.
He was following at a comfortable distance as Markus walked back toward the estate.
At a certain point, following at a comfortable distance through an unfamiliar city was the same as introducing yourself.
Markus stopped at a corner, turned, and looked at him.
The man stopped as well. He was Dominion-northern in his features, broad, carrying the specific quality of a practitioner who had been working in the mining sector rather than managing it — the calluses, the permanent cold-weathering of the skin, the tier-2 mana signature running at the calibrated efficiency of someone who had learned to conserve in an environment that burned through reserves quickly.
"You read the room for forty minutes," the man said, in accented Valerian. Accurate enough for complex sentences. "You're not a merchant. You're not a mercenary. The Fate's Eye technique is rare this far north." He paused. "I think you might be someone who is actually here to help."
Markus looked at him.
"Sven," the man said. "I work for people who have been trying to address what's happening in the southern quarter without the resources to address it."
"What's happening in the southern quarter," Markus said, testing the specificity.
"A contaminated distribution node," Sven said. "In the thermal fuel supply for the southern district's residential heating systems. Someone has integrated a mana-corruption formation into the distribution infrastructure. The population takes the contaminated fuel into their homes, burns it for heat, the corruption enters through the atmospheric exposure." He looked directly at Markus. "Whoever set this up understood corruption formations in detail, and understood the Citadel's infrastructure in detail. That's not a bandit operation. That's a faction with resources and patience."
He had just confirmed Valerian's intelligence through an independent source, which was the specific corroboration that made intelligence actionable.
"Do you know where the formation is," Markus said.
"I know where the fuel distribution hub is," Sven said. "I don't know how to address a corruption formation of this architecture. The practitioners I work with don't have the techniques."
Markus looked at him for a long moment.
"Do you have a map of the distribution infrastructure," he said.
Sven reached into his coat.
"I'll need to brief my team," Markus said. "Midnight. Can you be at this address?" He transmitted the estate's coordinates to Sven's watch.
Sven looked at the coordinates. Looked at Markus. The calculation he was running was visible in the quality of his attention.
"Yes," he said.
"Don't bring anyone who isn't already read into the situation," Markus said. "And bring the infrastructure map."
He turned and continued toward the estate.
He had the picture he needed. Now he needed to build the plan.