Sasuke woke to agony.
Different from the procedure. This was deep, bone-level pain. His entire body felt wrong. Like it didn't fit together properly anymore.
He tried to sit up. Couldn't. His muscles wouldn't respond.
"Don't move," Kabuto's voice came from nearby. "Your body is still adapting. Moving now could disrupt the integration."
Sasuke turned his head—barely. Kabuto sat at a desk covered in monitors and charts.
"How long?" Sasuke's voice was hoarse.
"Three days since the procedure. You've been unconscious the entire time." Kabuto approached with a glass of water. "Can you drink?"
Sasuke managed small sips. The water tasted strange. Everything tasted strange.
"What's happening to me?"
"Cellular reconstruction. The Hashirama cells are spreading through your body, replacing damaged tissue, integrating with your natural cells. It's why you feel wrong—your body is literally changing at the cellular level."
Kabuto pulled up a scan. Sasuke's body, displayed in detail. Areas of green chakra mixed with blue.
"The integration is proceeding faster than expected. Within a week, your entire cellular structure will be hybrid. You'll need to relearn your body's limits."
"Side effects?"
"Enhanced healing—minor wounds already close in minutes. Increased chakra reserves—approximately double your previous capacity. Stamina improvements. And..." Kabuto hesitated.
"What?"
"Your chakra feels different. Heavier. More potent. We won't know the full extent of changes until you're mobile again."
Over the next week, Sasuke slowly regained movement. First fingers. Then hands. Then arms. Each movement felt strange, like learning to walk again.
His body was different. Stronger. He could feel it. The Hashirama cells had fundamentally changed him.
On day eight, Kabuto removed the restraints.
"Try standing."
Sasuke swung his legs off the bed. Stood. The world tilted for a moment, then stabilized.
He felt... powerful. Like his body was packed with more energy than it could contain.
"How do you feel?"
"Different. Better." Sasuke clenched his fist. "How much stronger?"
"We'll test that. But first, we need to ensure the integration is stable." Kabuto handed him a kunai. "Cut your arm. Shallow cut."
Sasuke did. Blood welled up—
And the wound closed. Not instantly, but fast. Within thirty seconds, skin had sealed. Within a minute, not even a scar remained.
"Remarkable," Kabuto breathed. "Healing factor comparable to Tsunade-sama's Creation Rebirth. But passive. No jutsu required."
Sasuke felt his chakra. The reserves were massive. Easily double what he'd had before. Maybe more.
"When can I start training?"
"Eager, are we? Give it three more days. Let your body fully stabilize. Then we'll see what you're capable of."
Those three days felt like torture. Sasuke was trapped in the medical wing while his body completed its transformation. He could feel the changes still happening. Subtle shifts in his cellular structure. The Hashirama cells spreading to every part of him.
But finally, Kabuto cleared him for training.
"Let's see what you can do."