They stared at him like he'd just told them their new instructor was a squirrel in a vest.
Which, given some of the Barrier Corps' experiments, was not actually the weirdest thing Ren had ever heard.
"I'm not a chunin," he said to Jiraiya, answering his previous statement.
"You're joking," he said, skeptical. "You look younger than me."
Ren blinked slowly. "I am younger than you."
Jiraiya opened his mouth, then closed it, apparently unsure how to argue with that.
Tsunade's eyes narrowed, sharp as senbon.
"You're the vice captain?" she asked, gaze flicking to the insignia at his shoulder, then back to his face. "Of this division?"
"Yes," Ren said. "Have been for… a month and three days."
Her mouth twitched as if she couldn't decide whether she was impressed or irritated.
Orochimaru's gaze, in contrast, was almost unnervingly steady. He took Ren in from head to toe—mask, messy white hair, lithe and with ink stains on his fingers.
"And how long have you worked with seals?" he asked.
Ren tilted his head, letting himself think for a moment.
"Seven years," he said. "Seriously? Five. Before that, it was mostly making things explode by accident."
That earned him the tiniest quirk of Orochimaru's lips. Tsunade's mouth did a more obvious twitch.
Jiraiya snorted. "See, that's the part I understand."
Ren let that hang for a breath, then pushed off the table he'd been leaning against and clapped his hands once, lightly, to draw their attention.
"Before we start arguing about my birth certificate," he said, amused, "I'd like to know what you already know."
He gestured to the three low stools arranged opposite his own chair, facing the board he'd prepared.
"Please. Sit."
To their credit, they did. Jiraiya slouched. Tsunade sat like she was in a strategy meeting. Orochimaru folded himself down with a smooth, economical motion, posture perfect.
Ren took his own seat, brush in hand.
"Let's keep this simple," he said. "Tell me what fuinjutsu you've used or studied, and why you want to learn more. No trick answers, there's no grading."
He looked first to Jiraiya, mostly because the man seemed most likely to start losing interest if he wasn't engaged quickly.
Jiraiya scratched his cheek, thinking.
"I know basic storage seals," he said. "Explosion tags. The stuff they drilled into all of us at the academy. I can slap a simple barrier on a door if I need to make sure no one walks in on me in the bath."
"Important use case," Ren said gravely.
Tsunade rolled her eyes.
"Hey," Jiraiya protested. "Shampoo in your eyes is a stealth attack."
Ren hummed, not disagreeing. "And theory?"
Jiraiya shrugged. "I know they're important. I know they use chakra to hold effects. I know the Second was a genius and also insane for some of the things he came up with. And I got bored in the library a lot and kind of… skipped that section after a while."
"At least you're honest," Ren said. "And your reason for being here?"
Jiraiya spread his hands, unapologetic.
"We're grounded," he said. "No missions out of the village until the old man says so. I was going stir-crazy. Hiruzen-sensei said if I was going to be a nuisance, I might as well be a productive nuisance. I figured seals sounded more useful than learning to arrange flowers."
Ren dipped his brush in ink and made a small mark next to Jiraiya's name. Motivation: boredom + vaguely practical. That was workable.
His gaze shifted to Tsunade.
She met it without flinching.
"I know basic arrays," she said. "Storage, barriers, exploding tags, suppressants. I've helped maintain some of the hospital seals. And I'm working on a personal project."
Ren's attention sharpened.
"A personal project?" he echoed. "Related to fuinjutsu?"
"And medical chakra," she said.
There was a faint crease between her brows now, the look of someone who'd been wrestling with a problem for a while and was annoyed not at the problem itself, but at her own current inability to solve it.
"My grandmother gave me a prototype seal," Tsunade continued, voice losing some of its initial defensiveness as she slipped into explanation mode. "She didn't explain it in detail—said she didn't want to influence my approach with her methods. She wants me to… make it mine, I think. To finish it differently from how she would have."
Mito, Ren thought. Of course.
His gaze flicked, unbidden, to Tsunade's forehead.
Bare. No diamond. No seal yet.
He could guess what that prototype was. The Strength of a Hundred. A reservoir and regulator of chakra, tied into the body at a fundamental level. Storage and release and control, all in one place.
The sort of thing only a complete madwoman—or a genius—would attempt to create and then hand to her granddaughter as homework.
Kisuke would have adored her.
Ren did not ask to see it as some seals were personal.
"You asked for more thorough teaching because of this project," he said instead.
Tsunade nodded. "I can feel what it's trying to do," she said slowly. "I just… hit a wall when it comes to making it efficient enough not to kill the user. I know I'm missing something in the matrix. I don't have the vocabulary for it yet."
Ren tapped the end of his brush thoughtfully against the inkstone.
"I can't help you if I don't understand where you're stuck," he said. "But I won't ask to see the seal unless you want me to. You can describe the structure, or the functions you're trying to balance, and we can work through that."
She blinked, clearly surprised by the offer of distance.
Then, slowly, she relaxed a fraction.
"…That would be acceptable," she said.
He made another small mark by her name. Analytical. Personal stake. High potential. Dangerous project. Needs language.
His gaze slid at last to Orochimaru.
The pale shinobi sat very still, hands folded loosely on his knees. Of the three, he had said the least so far, but his eyes had missed nothing.
"And you?" Ren asked. "What have you worked with?"
Orochimaru didn't look away.
"The same basics they've mentioned," he said. "Tags. Simple storage. I've studied beyond that, but mostly from observation. Mission reports. Autopsies." His voice didn't change on the last word. "I'm familiar with the application of certain seals on… hosts."
Ren's fingers tightened infinitesimally on his brush.
If he had started working with Danzo, he hoped it was only prisoners he worked with. Cursed seals and experimental arrays are not something he would desire on an enemy, but he got the need of human experimentation, even if he didn't like it.
"So you've seen what fuinjutsu can do at its… worst," he breathed.
"You could say that," Orochimaru corrected. "I am interested in it because it offers some possibilities nothing else does."
Ren's mouth curved behind his mask.
Trust Orochimaru to instinctively get to the root of it.
"So that's your sole reason for being here?" he asked, though he already suspected.
Orochimaru's shoulders moved in the barest suggestion of a shrug.
"Tsunade requested instruction," he said. "We could not leave the village. Jiraiya was bored. I was curious."
Simple. Clean. Honest enough, in its way.
Ren sat back, weighing them.
Tsunade with her half-finished inheritance. Jiraiya with his restless energy. Orochimaru with his dangerous, focused curiosity.
Three different angles pointed at the same discipline.
He considered what to say for a moment, then set the brush aside deliberately and grabbed a piece of chalk.
"My name," he said, "is Ren Urahara. You can call me Ren-san, Urahara-san, Vice Captain, or 'hey you, the one with the brush,' depending on how well the lesson is going."
Jiraiya snorted. Tsunade's mouth twitched again. Orochimaru watched, eyes hooded.
"I'll be your instructor for as long as Hokage-sama thinks this is a good idea," Ren continued. "In return, I'll treat you like any other shinobi who comes here to learn. Rank and reputation excepted—because those only matter when filling out mission forms."
That got a real, if brief, grin out of Jiraiya.
Ren turned first to Tsunade.
"As for your project," he said, "I won't pretend I'm not curious. Anything Mito-sama created tends to be… interesting. But you're right to treat it as personal work. Like I said before, if you want help, I don't need to see the seal itself. Tell me the functions you're trying to juggle. Where the strain accumulates. Which parts feel inefficient when you run chakra through them. We can translate your instincts into matrices and see where the language is failing you."
Her eyes sharpened. "You think it's a language problem?"
"I think," Ren said calmly, "that you understand more than you can currently articulate. Once you can name the relationships, you'll see more ways to adjust them."
Her mouth quirked—not quite a smile, but something close.
"That would be… helpful," she admitted.
He inclined his head, then shifted his gaze to Orochimaru.
"Fuinjutsu doesn't just offer 'some' possibilities," he said. "It offers all of them."
Orochimaru's eyes narrowed just slightly at the affirmation.
Ren let the next words come out soft and matter-of-fact.
"If ninjutsu is the language of shaping chakra," Ren went on, "and taijutsu the language of shaping flesh, fuinjutsu is the language of shaping the rules of the world. It's… code, if you will. The grammar underneath reality as shinobi understand it. You set conditions, triggers, storage, flow, and you lock them into a pattern the world agrees to follow."
He could feel Orochimaru leaning toward him slightly, without moving.
"It needs preparation, yes," Ren allowed. "And years of study. You won't be slapping world-breaking seals on things after three lessons. But if you understand the principles deeply enough, you can, in theory, modify any system built on chakra. Re-route it. Suspend it. Translate it into something else entirely."
He let his gaze flick briefly to Jiraiya, then back.
"The Second Hokage understood this," Ren added. "That's why there are so many forbidden seals with his name on them. There are stories that he even created a technique to call the dead back. I've never seen the formula, and I hope I never do."
He let just enough dry humor into his voice to make it a deflection, not a challenge.
"But the point stands," he continued. "If you can define a phenomenon, you can, eventually, write a seal that touches it. Pain. Memory. Distance. Time—though that's a very bad idea and you should never bring me a proposal about it," he added, glancing at Jiraiya just in case. "Fuinjutsu can be used to bind, protect, heal, share, store, destroy. The limits are your imagination and your willingness to deal with the consequences."
Orochimaru's fingers tightened minutely on his knees.
Jiraiya shifted, mouth slightly open, as if he'd never thought of it that way before.
Tsunade's eyes were distant, already slotting what he'd said against the prototype seal waiting in her desk drawer.
Ren let the silence stretch for a moment, then broke it gently.
"As for you, Jiraiya-san," he said, turning his attention fully to the tallest of the three. "You came here because you were bored. That's fine. Boredom is a good starting point. It means you have room."
Jiraiya frowned, wary. "Room for what?"
"Curiosity," Ren said simply. "If I do my job right, you'll leave this course with at least one aspect of fuinjutsu you actually like. Something you're proud of. Maybe that's storage. Maybe it's traps. Maybe it's building a seal that makes sure no one ever walks in on you in the bath again."
Tsunade made a strangled sound that might have been a laugh.
Ren continued, unbothered.
"If I fail," he added, "you'll still leave knowing enough not to blow yourself up. That's my minimum standard."
Jiraiya stared at him for a second, then huffed out a breath that was almost a grin.
"Alright, Urahara," he said. "If you can make these 'pretty symbols' interesting, I'll… take this seriously."
"Acceptable terms," Ren said.
He pushed himself to his feet, picked up a piece of chalk, and turned to the blank board behind him.
"Good," he said. "Because we're starting from the very beginning."
There was a chorus of groans, one louder than the others. He smiled faintly, drawing the first simple circle.
"Not that beginning," he clarified. "Not what you've memorized. The actual beginning. What a seal is. By the end of today, I want you to be able to look at any basic array and tell me not just what it does, but why it works."
Three sets of eyes watched the circle take shape.
Benihime, in the back of his mind, hummed approvingly.
Ren drew the first line through the circle—input, output, condition—and thought, as chalk scratched softly against the board, that whether he liked it or not, his quiet plan to stay on the edges had just been rewritten.