The air in the little room went wrong before the door moved.
Kakashi straightened from the cot, every lazy line in his body quietly erased. His hand drifted up, two fingers hooking under his hitai-ate.
That chakra.
Even dulled by stone and distance, it was unmistakable. Cold and slick, like oil poured over river rock. It slid along his skin without quite touching, full of old battlefield memories and the stink of experiments gone right in the worst way.
The latch clicked.
The door opened without a sound.
Orochimaru didn't so much walk in as flow into the doorway. He leaned against the frame like they were in some corridor at the Academy and he'd just happened to stop by.
"Kakashi-kun," he said, voice low and amused. "You've grown up."
Pale skin, yellow eyes ringed in purple, hair dark and straight as spilled ink. The Konoha hitai-ate was gone, but the outline of where it had rested might as well have been tattooed on his forehead.
Kakashi slid his hitai-ate up.
Sharingan snapped into focus, taking in everything at once: the way Orochimaru's weight rested on the balls of his feet, the angle of his shoulders, the lazy twirl of his fingers against the doorframe.
The way his chakra filled the room like a gas, invisible and everywhere. And under it, the awareness of Sasuke's sleeping form on the cot behind him, small and vulnerable and branded.
"Orochimaru," Kakashi said. "You're as subtle as ever."
Orochimaru's lips curled. "Says the man who drags a child into a side room to play with seals behind everyone's backs."
His eyes slid past Kakashi toward the cot.
Kakashi stepped sideways, blocking the line of sight without making it a big show. "Professional courtesy," he said. "We put warning labels on dangerous toys."
He could feel the sealed mark under his palm from earlier like phantom heat. Orochimaru's chakra had sunk deep, like rust eaten into steel, and his own seal sat over it like a fresh plate bolted on top.
It would hold. For now.
Orochimaru tilted his head. "You really think you can overwrite my work?"
"I don't have to overwrite it," Kakashi said. "Just keep it from spreading until he's old enough not to let it eat him alive."
"Old enough." Orochimaru's voice went soft and delighted, like someone tasting a word. "You mean, old enough that his body is ready for me."
Kakashi's fingers twitched.
"That boy is my student," he said.
One of Orochimaru's eyebrows arched lazily. "Is he? How… possessive. I don't recall that stopping you from failing the last Uchiha you had such high hopes for."
Heat pricked behind Kakashi's ribs. Obito's face flashed through his mind—the grin, the blood, the crushed half of his body under rock.
The Sharingan whirred, tomoe spinning once before settling.
Orochimaru watched it with an almost tender fascination.
"Such a precious eye," he murmured. "To think you keep wasting it on this village's errands. On little games like this." His tongue flicked out briefly between his teeth. "If you're worried about the boy, you could always give him your other one. Make him stronger. I hear it runs in the blood."
"You don't get to talk about his blood," Kakashi said. His voice stayed even, but the room felt tighter.
Orochimaru's gaze sharpened.
"There it is," he said. "That little iron core they say you have. The Copy Ninja. A thousand jutsu in your head and still you stand between me and what I want with only that eye and some ink."
He pushed off the doorframe with a casual roll of his shoulder, taking one slow step into the room.
Kakashi's muscles screamed move. He pictured a dozen sequences in the span of a breath: Sharingan pre-reading Orochimaru's first lunge, a Raikiri up through that pale chest, smoke bombs, back wall, window—
And then the rest of the math finished.
He was tired.
The sealing had dragged more chakra out of him than he wanted to admit. He'd been coasting on reserves since the Wave mission, since the fight with Zabuza and the clone in the ice. His lungs still remembered nearly drowning.
Orochimaru, by contrast, felt like a deep well that never saw daylight.
If Kakashi started a real fight here, in a box room with one unconscious genin and nowhere for civilians to run, he could maybe cut something important on the way down.
He would also die.
And Sasuke, with his brand and his bright, burning hatred, would be left alone with the man who put the mark on him.
Not an option.
Kakashi let his fingers fall away from his chest, deliberately not making the seal that would start Raikiri crackling in his hand.
"Funny thing about a thousand jutsu," he said, eye half-lidding in what looked like boredom. "You learn which ones not to use."
Orochimaru chuckled. "You always were clever."
His gaze drifted to the floor, tracing the ink pattern of the seal.
"Five Elements, hm?" he said. "Neatly done. Enough to baffle the instructors. Enough to reassure your Hokage. But you know as well as I do—" he raised his eyes again, smile thin, "—you're just putting a lid on a pot that's already boiling."
Kakashi shrugged. "That's still better than letting you play chef."
"Harsh," Orochimaru said lightly. "Don't you want to see how far he could go?"
Kakashi's jaw ached. "I want to see him live long enough to decide that for himself."
"Ah." Orochimaru's expression cooled.
For a moment, the lazy playfulness dropped. The thing looking at Kakashi wasn't a wayward student or a disgruntled ex-Leaf shinobi. It was a predator that had outlived too many prey.
"That's where we differ," Orochimaru said quietly. "I don't trust children to make good choices about power."
His gaze slid past Kakashi again, over his shoulder this time, measuring the shape of Sasuke under the blanket without needing to see the brand.
"So," he said. "Allow me to be clear, Kakashi-kun. If you get in my way…" His chakra tightened, just enough that the air felt too thin. "I will kill you."
Kakashi held his eye.
Under the flippant, under the half-smile, his body was coiled to move if anything shifted wrong. Every inch of him was cataloguing: how long Orochimaru's fingers took to curl, how fast his chest rose, the micro-twitches at the corners of his eyes.
No opening.
Not one that didn't come with a matching coffin.
"Good to know," Kakashi said. "I'll put it in my notes. Right under 'Snake freak with bad taste in jewelry.'"
Orochimaru laughed.
It was a small thing, soft and almost genuine. "Still trying to make light of it," he said. "You must be very tired of funerals, Copy Ninja."
Kakashi didn't answer that.
Orochimaru let the moment hang, savoring it like a cat deciding not to pounce.
"Oh well," he said at last. "We have time. I'll let you babysit him a little longer. That brand of mine…" His eyes hooded. "It isn't something you can erase."
He rolled his shoulders, like a snake testing its length.
Then his chakra pulled back.
It was like watching shadow peel away from the walls. Orochimaru stepped backward and simply… wasn't there anymore. One blink, and the doorway held nothing but empty hall and the faint scent of damp earth.
The room felt bigger without him. Colder, somehow.
Kakashi exhaled slowly.
His Sharingan burned. He tugged the hitai-ate back down over it with a practiced motion, grateful for the dull pressure over the eye.
Behind him, Sasuke slept on, oblivious.
Kakashi looked at the boy's face for a long moment. Relaxed, without the usual tension in his brow, he looked younger. Too young for snake brands and Sannin interest and the weight of a clan's ghosts.
"Rust and poison," Kakashi murmured. "I'll clean what I can."
Outside, the distant roar of the arena swelled again, then punctured into scattered cheers. Another match finished.
Kakashi dragged a hand through his hair and straightened.
He had just enough chakra left to get Sasuke back to the others and pretend, for a little while longer, that this was still just an exam.
He turned toward the door—
And paused.
Something was moving in the corridor. Not Orochimaru this time. Smaller. Brighter. Wobbly around the edges.
He felt it before he heard the footsteps.