Rakh’ash’tha arrived at the Tekarr Arch on the fourth morning after Aliyah’s signal, with the mountain cold sharp in the air and the orcish security contingent’s watch fire visible from half a mile out. The deviation reading when the healer walked through the research chamber door was fifty-one percent.

Aliyah was at the instrument. She had been at the instrument for most of the past four days, sleeping in the chair when the readings allowed it rather than walking to the sleeping room, because the readings required monitoring at a frequency that the room’s distance made inconvenient. Darak sat at the table behind her with the measurement charts spread across every available surface and the hollow-eyed alertness of a researcher running on insufficient sleep because the data was too important to stop watching.

"The rate is holding at three to four points daily," Aliyah said, before Rakh’ash’tha had set down the travel pack. "No acceleration yet. The cycling pattern has not changed."

"I need the last seventy-two hours of readings," the healer said. "And quiet while I work."

Darak cleared one end of the table without being asked. He had worked alongside Rakh’ash’tha before, during the earlier coordination on the Healer’s Codex, and he knew the specific quality of focus the healer brought to a problem: total, methodical, not to be interrupted. He moved the charts he needed to the other end and went back to his own work.

The analysis took two hours. Rakh’ash’tha worked through the measurements with the spectrometric instruments Aliyah had provided, cross-referencing each reading against the baselines, building the picture in the patient methodical way that medical training built into habits. Not looking for the expected pattern. Looking at what the pattern actually was, which was different work.

The healer stopped at the readings from the third day.

"There are two rhythms," Rakh’ash’tha said.

Aliyah turned from the instrument.

"The cycling pressure has two distinct intervals embedded in it." The healer traced the measurement line across Darak’s charts with one finger, not touching the parchment but following the line precisely. "Here: the push phase lasts four seconds and then releases. But every third cycle, the push phase lasts a bit longer than the rest. The difference is small but it is consistent. Too consistent to be variation. A natural variation at that scale would drift. This does not drift. It repeats at the same interval, at the same duration, every time."

A pause. "Two entities. Not perfectly synchronized. When one releases its pressure, the other maintains it. They trade the load between them so neither exhausts itself in a sustained push."

The chamber was quiet except for the low ambient hum that the Arch produced at close proximity, a sound Aliyah had stopped consciously hearing years ago but that Rakh’ash’tha could feel as a vibration in the stone floor through boot soles.

Aliyah sat down on the stone bench and looked at the Keystone. "Coordination," she said. "Coordination implies communication. Something on the other side of this binding can communicate with another entity in the Abyss at the intervals and precision this cycling requires."

"At minimum," Rakh’ash’tha said carefully. "What I can see in the readings is the output of the coordination. The communication itself, whether it is ongoing or whether it consisted of an agreed plan that both entities are following independently, I cannot determine from the readings."

"Does the distinction matter?" Darak asked from his end of the table.

"It matters for the response," Rakh’ash’tha said. "If they are communicating in real time, disrupting the communication disrupts the coordination. If they are following a pre-agreed plan, disrupting a communication link does nothing. The plan continues."

Aliyah was looking at the Keystone. "We have no mechanism for disrupting communication through a sealed dimensional binding. The seal is not porous in that direction. So the distinction matters only theoretically."

"Then practically," Rakh’ash’tha said, "what matters is this: we are not dealing with one entity applying pressure. We are dealing with two entities working a plan. And if they can coordinate against one Keystone, they can coordinate against seven."

Darak said, from behind his charts: "If the coordination extends beyond this Arch, the entire network may be under simultaneous pressure at different stages. Each Arch experiencing what it experiences as a single-source local problem, none of them aware that the problem is the same problem expressed across twelve locations."

The silence held all three of them for a moment, each working through the same implication from a different position.

"How many Archs are in the active network?" Rakh’ash’tha asked.

"Twelve," Darak said. He had looked this up two days ago, pulling the Order’s organizational register from the document chest because the number had become relevant in a way it had not been before. "Including Tekarr."

Aliyah stood from the bench. She moved to the writing materials with the specific directness of someone who had held a decision in suspension while the analysis completed and was now ready to act on it.

"Send a message to every active Arch today. Ask for their complete deviation readings for the past eight weeks. Do not explain why. Just ask for the readings. A request for readings without an accompanying explanation will itself tell the Wardens something has changed, which is information enough for them to increase their monitoring frequency."

She was already writing as she spoke. "Send a separate message to the Order’s council. Tell them the Tekarr Arch is under coordinated pressure from multiple entities and that I believe the network is being probed at multiple points simultaneously. Tell them I need practitioners. Not eventually. Now."

"The council will want to convene before sending practitioners," Darak said.

"Tell them to convene fast." She did not look up from the writing. "Rakh’ash’tha, I need you to examine the other six Keystones. Not with the instruments. With your hands. Tell me if any of them feel wrong in the way the third one felt six weeks ago before the instruments caught the deviation."

Rakh’ash’tha moved to the chamber entrance. "And if something does feel wrong?"

"Tell me immediately. Then we decide together what comes next." Aliyah sealed the first letter. "Whatever we decide will be better than deciding alone, which is what I have been doing for the past four days."

Rakh’ash’tha examined the remaining six Keystones that evening while Aliyah wrote the urgent correspondence to the Order’s Chapter. The examination took forty minutes, working slowly with both hands on each stone’s housing, building a tactile understanding of what normal felt like before trying to identify what was not normal.

Five of the six were stable. The sixth was the Keystone in the east-facing socket, the one that received the least direct light from the chamber’s braziers. It was not wrong in the way the third was wrong. It was quieter than it should have been. Like a presence that had stopped moving and was holding very still.

Rakh’ash’tha stood at the sixth Keystone for a long moment without moving, then stepped back and went to find Aliyah.

"The sixth," the healer said. "It is not under active pressure. But something is attending to it. Waiting."

Aliyah stopped writing. She looked at the Keystone chamber’s doorway. Then she added a line to the message she was composing: six Keystones require active monitoring. All of them. Not three. All.