Kisuke Urahara noticed it because it bothered him.
It didn't alarm him. It didn't scare him.
Bothered him.
Ichigo's reiatsu behaved correctly, too correctly, except for one detail that refused to align with everything Urahara knew about cause and effect.
It arrived late.
Urahara, tapping the ground with his cane:
"Stay there, don't do anything heroic."
Ichigo shot him a look:
"You say that like I do it on purpose."
Urahara smiled faintly and adjusted the lenses of a device attached to the wall of the underground training space. The air hummed softly with the Kidō arrays layered so thinly that they were almost invisible.
Urahara, smiling:
"Just relax, pretend you're not being watched by someone with an unhealthy interest in spiritual anomalies."
Ichigo, frowning:
"That doesn't help."
Urahara responded happily:
"Ah, good. That means you're reacting normally."
Ichigo got into position. He felt it again - that pressure in his chest, not sharp enough to hurt, but persistent, as if gravity was pulling him from a direction he couldn't point.
Urahara raised his cane.
Without warning, he struck the ground.
The sound pierced the space.
Ichigo flinched, half a second too late.
Urahara's eyes narrowed.
Urahara, pacing slowly:
"Again."
This time, he released a brief pulse of spiritual pressure - it wasn't an attack, just a threat. Ichigo felt it wash over him, dull and distant.
Ichigo's reiatsu skyrocketed.
After.
Urahara stared at the display monitor floating in the air between them, lines of light tracking Ichigo's spiritual output in real time.
Urahara murmured:
"Fascinating."
Ichigo frowned:
"Are you going to explain that or are you going to keep doing the creepy scientist thing?"
Urahara, his tone light, but his eyes had sharpened:
"Oh, I'll explain, I just want to be very sure I'm right first."
Urahara moved quickly now, placing markers, adjusting stamps. Another stimulus - a thrown object. Another peak. Another delay.
Consistent. Measurable.
Wrong.
Urahara stood up straight and tapped the reading with his cane:
"Your reiatsu is not weaker, it's not suppressed. It's not unstable."
Ichigo crossed his arms:
"That's good, right?"
Urahara replied:
"It would be, if it weren't late."
He turned the projection so Ichigo could see it clearly.
Urahara continued:
"Normally, a stimulus - threat, emotion, intention - occurs and your spiritual pressure responds immediately. Sometimes it even anticipates it. That's instinct."
Ichigo watched the line trace itself through the air, peaks and valleys offset by the marked stimuli.
Ichigo, quietly:
"And not mine."
Urahara corrected:
"Oh, it does, just not in time."
Urahara walked slowly:
"This is not a hesitation, and it's not indecision. Your body and mind are responding at the right speed."
Urahara touched the projection again:
"But your soul is slightly out of step."
Ichigo felt his stomach clench:
"Out of step with what?"
Urahara didn't respond immediately.
Instead he reached into his sleeve and pulled out the Substitute Soul Reaper Badge. He held it loosely in the palm of his hand, letting the chain dangle.
The badge felt cold.
Colder than it should be.
Urahara frowned and then looked back at Ichigo at last:
"With something it is connected to."
Ichigo swallowed:
"Rukia."
Urahara did not confirm it.
He did not deny it either.
Urahara instead said:
"Think about it this way, if two systems are linked and one undergoes a structural change... the other experiences feedback."
Ichigo clenched his fists:
"So, whatever is going on there..."
Urahara finished:
"...it's stabilising, not fluctuating. Not reacting. Stabilising."
Urahara gestured toward the display monitor again:
"Your reiatsu tries to match that stability. But you're human. You respond to the world through emotion, instinct, impulse. Those come first."
Urahara looked back at Ichigo:
"Your power follows later."
Ichigo exhaled slowly:
"So I'm slower."
Urahara, frowning:
"Not exactly, you're out of sync."
Urahara smiled slightly, although there was no humour in it:
"Which is much worse."
Urahara deactivated the array and the light went out in the room:
"This type of compensation does not occur naturally, it means that something on the other end of your link has stopped responding to stimuli the way a person does."
Ichigo's voice was strained:
"She is not conscious."
Urahara agreed quietly:
"No, which means this isn't communication."
Urahara tapped the badge once:
"It's compensation."
Silence settled between them.
Ichigo looked at his hands. They looked the same. He felt the same. Strong.
And yet...
Ichigo asked:
"What if it gets worse?"
Urahara didn't respond immediately, then spoke carefully:
"If the compensation increases, your reactions will continue to lag. Over time, your power will arrive after the time it is needed."
Ichigo looked up sharply:
"So I lose fights."
Urahara nodded:
"You survive situations you shouldn't. Or someone else doesn't."
The words landed hard.
Urahara turned around, adjusting something on a shelf with unnecessary precision, then speaks lightly:
"The good news, is that this tells us a lot."
Ichigo asked:
"And the bad news?"
Urahara looked back over his shoulder:
"It tells us that the system on the other end is working exactly as expected."
Ichigo felt the pressure in his chest tighten.
Not pain.
Not fear.
Just drag.
When Ichigo left the shop later, the world felt normal again - street lights, passing cars, distant voices.
A cyclist suddenly swerved in front of him.
Ichigo took a step back.
A heartbeat later than it should be.
His pulse quickened afterward.
He stood still for a moment, then continued walking, his jaw clenched.
Somewhere far away, something that didn't think, didn't feel, and didn't know its name continued to stabilise.
And Ichigo Kurosaki moved during the night slightly out of step with the world. Not weaker, not broken, but untimely.