The teal thread did not still and it did not vibrate.
It sang.
Not sound — nothing so literal. But a resonance that Kael felt along the back of his teeth, in the hollow behind his sternum, in the exact place where the pull lived when it was moving. The thread moved in a long, slow oscillation, back and forth, like something measuring a tide rather than a moment. Like something tracking a thing that did not stop.
Casvar pulled the instrument back slowly and held it at arm's length and looked at the thread's motion with the face he made when he was doing arithmetic in a language that did not have numbers for what he was counting.
He said: "The third instrument measures accumulation."
Kael said: "What am I accumulating."
Casvar set the instrument on the bench with the same careful precision he had used for the dark-threaded one. He said: "The energy that passes through the Fractures of the dead when they die — it does not disappear. In a person with Fractures of their own, it passes through and disperses. It finds the channels already cut and runs out through them."
He paused.
He said: "You have no channels."
Kael thought about water hitting a surface with no outlet. He thought about pressure.
He said: "So it stays."
Casvar said: "It accumulates. Every dead thing your pull has touched — the eleven in the ash field, the animal in the courtyard, the three in the alcove, every preserved body you have walked past in these corridors — each one has left something in you. The teal thread can feel it. More than expected, faster than expected, and now more than that."
He looked at Kael with the expression that had no warmth and no coldness and was, in its absolute accuracy, the most honest thing in the room.
He said: "The Kaer four hundred years ago accumulated for twelve years. You have been here thirty days."
The silence after that had weight to it, the way the silence in the eastern wing had weight — not empty, but full of the shape of something that had already happened somewhere else.
Kael breathed slowly. He directed the pull inward the way Casvar had shown him, narrowing the tide rather than stopping it, running it through a channel that did not exist but that discipline could approximate.
He said: "Can it be released deliberately. Before it reaches — that."
Casvar said: "That is what I intend to teach you. Whether it can be learned in time is the open question."
Kael said: "In time for what threshold."
Casvar looked at him. He said: "When the teal thread begins to arc instead of oscillate, we will have three weeks, perhaps four, before the accumulation becomes structural. Before it is part of you in a way that deliberate release cannot address."
Kael said: "And then."
Casvar said: "And then it releases itself. And we will need a larger building to lose."
He said it the same way he said everything — as assessment, not threat, not comfort. The fact of it placed between them for use.
Kael sat with it. He thought about the field of ash and the eleven bodies and the animal in the courtyard and the cold, permanent pull that had been moving through him since Tuesday. He thought about what it meant that the thing he had thought was leaking out of him was, in some portion, staying.
He said: "Show me how to release it."
Casvar said: "Not today. Today you learn what you are holding. You cannot release a thing you have not yet understood the shape of."
He opened the case again. He arranged the three instruments in a row on the bench. The pale one still. The dark one oscillating steadily. The teal one singing its slow, deep measurement.
He said: "Look at them. This is what you are."
Kael looked.
He thought: a man with no wounds, an echo the instruments can barely find, and something accumulating where the channels should be but aren't.
He thought: in his world he had carried bags of groceries. He had stocked shelves. He had been careful not to trouble anyone.
The teal thread moved in its long, slow arc.
He breathed. He held it. He waited.