Serou's house. Two days later.
By the third session, Kaito had stopped asking whether the training was dangerous.
It was.
That was no longer useful information.
The useful question was how much danger he could carry back with him before it stopped being training and became damage.
That morning, Serou placed six paper seals on the flat stone table in the main room.
Each one was different.
Some were simple binding structures. Some were layered with misdirection. One of them had no obvious core at all.
Kaito stood across from the table, arms folded in his sleeves, eyes moving from one seal to the next.
Serou stood at the far wall.
"Choose the damaged one."
Kaito did not touch the seals.
"Only one is damaged?"
"Only one matters."
Kaito leaned slightly closer.
The room was silent except for the faint movement of cloth whenever Serou shifted his weight.
Normally, Kaito would have approached this like a puzzle.
Study the ink density.
Check the brush pressure.
Observe whether the construction was balanced or asymmetrical.
But this time, he did something different.
He let the residue of the morning practice settle.
The calm layer.
The threshold.
The cut.
He did not enter the seal inside him—not fully, not even close.
He only tilted his awareness toward it.
Immediately, something changed.
The seals on the table were still paper and ink.
But not only that.
One of them felt wrong.
Not broken in shape.
Not broken in logic.
Broken in intent.
Kaito's eyes shifted to the fourth strip from the left.
He said, "That one."
Serou did not move.
"Why?"
"The structure is pretending to be incomplete." Kaito kept his gaze on it. "But the incompleteness is deliberate. The outer line wants the reader to think the flaw is there."
"And?"
"The actual instability is under it." He pointed. "The return path bends too early. If activated, it wouldn't fail immediately. It would hold just long enough to collapse after commitment."
Now Serou moved.
He came to the table, picked up the fourth seal, and turned it over once between his fingers.
Then he set it down again.
"Correct."
Kaito looked at him.
Serou rarely gave direct confirmation so quickly.
"What was it for?" Kaito asked.
"A capture seal."
"Lethal?"
"Not at first."
Kaito was silent for a moment.
Then he asked, "Did you make it?"
"Yes."
"Why?"
"To see whether you could notice something that wasn't wrong in structure, but wrong in will."
Kaito lowered his eyes to the table.
The phrase stayed in his mind.
Wrong in will.
That was exactly what it had felt like.
Not faulty.
Deceptive.
He looked at the other seals.
"Can I try the rest?"
Serou's gaze sharpened slightly.
"Why?"
"Because if I only test once, I won't know whether I sensed the seal... or guessed correctly."
A pause.
Then Serou nodded once.
"Try."
Kaito moved through them one by one.
The second was honest and crude.
The fifth was elegant but unstable by age, not by intent.
The first was harmless.
The sixth was unfinished.
And the third—
He stopped at the third.
Not because it was damaged.
Because it felt... hostile.
Very faintly.
Like a blade wrapped in cloth.
"This one is complete," Kaito said. "But it doesn't want to be touched."
Serou took longer to answer this time.
Finally, he said, "It is a trigger seal."
Kaito looked up.
"For what?"
"If tampered with incorrectly, it informs the one who placed it."
Kaito's eyes narrowed.
"So I was right."
"Yes."
Serou stepped closer to the table and gathered the seals back into his sleeve.
When he was done, he said quietly,
"The seal inside you is beginning to change how you read things."
Kaito looked at his left wrist.
The mark was faint now, almost hidden.
"Only seals?"
Serou's silence was brief.
"No."
That single word altered the room.
Kaito asked, "What else?"
"Not yet."
"That means you know."
"That means I suspect."
Kaito held his gaze.
Serou said, "If the living seal continues to develop through resonance rather than force, then it may start showing you fractures before they become visible."
"In seals?"
"In people." Serou's voice remained even. "In intentions. In decisions. In danger."
The room was quiet again.
Kaito looked at the stone table without seeing it.
The first ability had been internal.
Now this.
He thought of Root.
Of hidden structures.
Of people who lied without changing expression.
He said, "That would make me useful."
Serou watched him carefully.
"Yes."
Kaito raised his eyes.
"And easier to hunt."
This time, Serou nodded.
"Yes."
The answer did not frighten him as much as it should have.
That unsettled him more than the answer itself.
At dusk, during the next threshold exercise, the new problem appeared.
Kaito entered the threshold.
Held.
Cut.
Returned.
But when he opened his eyes, Serou had not spoken yet.
And still, Kaito knew what he was about to say.
Not the words.
The direction.
Caution.
Approval buried underneath it.
And concern behind both.
He blinked.
The sensation vanished.
Serou noticed.
"What happened?"
Kaito took a second too long to answer.
"That depends," he said slowly. "Did you just decide to stop the session?"
Serou's eyes changed.
Only slightly.
"Yes."
Kaito exhaled once through his nose.
"I knew before you spoke."
Now Serou was fully still.
"What did you know?"
"Not the sentence. The shape of it."
Silence.
Then Serou asked, "How certain?"
"Enough that if you had said the opposite, I would have been surprised."
Serou looked away for a brief moment, then back at him.
"The residual effect has started."
Kaito said nothing.
Serou stepped closer.
"From now on, after every return, you tell me exactly what remains."
"Every time?"
"Every time."
Kaito nodded once.
That night, while reading in the main room, he felt it again.
Not from Serou this time.
From the old kettle near the fire.
He looked at it.
At first, he thought he was imagining it.
Then he understood.
The bottom edge had a hairline crack.
Invisible unless turned toward the light.
He stood, crossed the room, lifted it, and tilted it.
There it was.
A fracture.
Serou looked up from his book.
Kaito held up the kettle.
"It was going to split."
Serou said nothing for three full seconds.
Then he closed the book in his lap.
"When?"
"Soon," Kaito said. "Very soon."
Serou took the kettle from him, examined it under the light, and found the crack exactly where Kaito had seen it.
He placed it down carefully.
Then looked at Kaito.
And for the first time in days, he said something without distance.
"Good."
Kaito blinked once.
Serou added, quieter this time,
"That one is actually praise."