Black Zetsu had been around powerful people before. Across thousands of years, the category had included individuals who redefined what the word meant in their respective eras. He had watched enough of them arrive and move through the world to understand that the visceral impact of proximity was a response to a real thing, not a fabrication of inexperienced nerves.
He registered what Uchiha Obito was still absorbing and set it aside.
"Lord Finn," he said, after Finn's greeting had settled into the air. "We imposed on your time. The wait was ours to bear, not yours."
Finn's smile widened slightly. "Generous of you. Though let me be direct, since we're all here: the arrangement we discussed doesn't change. I'm not invested in your plan. What I'm doing is using the same evening you are, in the same location, for my own purposes. You create the conditions, Obito extracts the Nine-Tails, and when that part is done and it's time to leave, I'll put cover between you and anyone trying to follow. That's the extent of my involvement in your side of this."
"Understood completely," Black Zetsu said, with no hesitation at all. "Whatever serves you, Lord Finn."
Finn nodded.
He understood, with considerable clarity, how this night was actually going to unfold. In the original sequence of events, Uchiha Obito did not extract the Nine-Tails and evacuate cleanly. Obito extracted the Nine-Tails and then turned around and sent it at Konoha. The attack on the village, the deaths, the sealing into the newborn child: all of that was part of Obito's intended sequence, not a deviation from it. There was no clean extraction followed by a retreat that needed covering.
Which meant the "cover the retreat" obligation Finn had nominally agreed to was going to dissolve on its own when Obito broke the agreement by not retreating. At that point Finn would be free to attend to his own objectives without any contractual entanglement.
Black Zetsu presumably understood this as well, and was presumably planning around it in his own way, and was presumably content to let the current framing stand because the current framing kept Finn cooperative through the evening's early stages.
Finn was happy to let Black Zetsu be comfortable for a while longer.
"Shall we get moving?" Finn said. "The road between Rain Country and the Land of Fire isn't short."
Uchiha Obito straightened. He'd found his footing again, the momentary disruption smoothed over by the act of having something to do. He patted his chest once in the gesture of someone volunteering before the request was fully formed.
"There's no need to travel by road," he said. "My technique can take us directly to Konoha. All three of us."
Finn raised an eyebrow, and the interest in it was genuine, if not for the reasons Obito was reading.
Kamui. Long-distance spatial transportation, multiple passengers, cross-country range. The technique had demonstrated capabilities in the original timeline that placed it in a different category from the spatial shortcuts most shinobi used. When Uchiha Sasuke had been nearly killed fighting Danzo at the Kage Summit, trapped in the Iron Country with nowhere to go, it had been Kamui that pulled him clear, extracting him from inside Danzo's desperate final sealing technique at the last possible instant. That particular feat, the precision it had required, the range involved, had told Finn everything he needed to know about what Kamui could do at its upper limits.
"Space-time ninjutsu," Finn said, with the tone of someone making a pleased discovery. "That's genuinely rare. I haven't seen anything quite like it. I'm looking forward to it."
It was a simple compliment, delivered without particular emphasis.
It landed on Uchiha Obito like sunlight on cold stone.
Behind the mask, something restructured itself. The slightly compressed posture of someone maintaining a performance they weren't fully confident in loosened in the specific places where actual pride doesn't need performance. He was very powerful. Even someone of this level acknowledged it directly.
He was, in that moment, exactly the young man he was trying not to appear to be, pleased in the uncomplicated way of someone who has been recognized for something they've worked very hard on.
His voice came out measured, with visible effort. "It opens your eyes a bit, doesn't it."
Finn gestured: lead the way.
Obito reached out to Black Zetsu with his left hand, gripped his arm just below the shoulder, and extended his right hand toward Finn. "Hold on."
Finn looked at the hand, then at the arm, and took the arm instead. A minor divergence. Obito filed it without objecting.
"My technique moves fast," Obito said. "Just brace yourself."
Something about the phrasing tickled Finn's sense of the absurd. He suppressed it.
Obito's Mangekyō Sharingan activated. The specific pattern of it was visible even through the mask's single eyehole, the tomoe structure of the Kamui rotating as the space around all three of them began to behave incorrectly. Not collapsing, not folding in the usual metaphorical sense that people used to describe space-time techniques. The geometry of the immediate environment began to draw toward a single point, like water finding a drain, and the drain was the Mangekyō.
Finn felt it before the visual effect became pronounced.
It was a quality of energy he had last encountered in a different world entirely, when the accumulation of it across years of specific experiences had reached some threshold and deposited him somewhere he hadn't been before. The same quality, faint here, present here, coming off Kamui in the way heat comes off something operating at high temperature.
He absorbed it.
Not as a decision. His body did it the way it processed natural energy, automatically, the moment proximity made it accessible. A very small amount. A fraction of what he'd hoped, certainly far less than the years of accumulated space-time energy that had eventually carried him between worlds. But it was there, and it was real, and it was inside him now.
The world around them became the inside of Kamui's transit dimension and then resolved into a grove of trees in the Land of Fire, outside Konoha's walls, in the space of what felt like a single compressed moment.
Obito let go and took one breath that was slightly more deliberate than the breaths preceding it. He had been expending more chakra than expected. Significantly more. He hadn't brought passengers through Kamui many times at this scale, and the consumption felt disproportionate to the adjustment.
He attributed it to the additional weight. Two passengers instead of one, or effectively one where the Zetsu were concerned. He resolved to account for it in future applications.
Finn stood in the grove and felt the trace of space-time energy settle into whatever it was settling into. He ran a quiet internal assessment.
It was minuscule. As a fraction of what would eventually be needed for intentional world-crossing, it barely registered. But the significance wasn't scale, it was confirmation. The energy could be absorbed. Kamui produced it. The path existed.
Orochimaru had been correct: substitution techniques, summoning techniques, everything in the category of incidental spatial manipulation, produced none of this. Finn had performed those techniques hundreds of times and had never absorbed a particle of it. Kamui had carried him two hundred kilometers in an eyeblink and produced a measurable deposit on the first attempt.
He looked at Uchiha Obito with an expression that Obito found somewhat difficult to interpret.
"Remarkable," Finn said. "I don't think I've experienced anything quite like that. The technique is genuinely extraordinary." He paused. "I hope I'll have the opportunity to travel by Kamui again before long."
Obito's back straightened by approximately two centimeters.
He had been running on the faint worry, suppressed but present, that the chakra expenditure had been visible and embarrassing. Finn's praise dissolved that concern with the efficiency of something that had been waiting for exactly this input.
My Kamui is extraordinary. Even he acknowledges it. I haven't even fully developed it yet, haven't finished processing what Madara's inheritance contains. When I'm at full capacity...
He let himself think forward, briefly, to a version of himself that had integrated everything, that had acquired what he needed from the Uchiha clan, that had grown into what he was becoming. He would get there. He could feel the distance between here and there, but he could also feel that it wasn't fixed.
"Happy to," he said, with the generosity of someone disposing of an inexhaustible resource. "Leave it to me."
Black Zetsu watched this exchange and experienced the quiet satisfaction of things arranging themselves in useful directions. Finn and Obito had just voluntarily agreed to a recurring collaborative interaction with mutual benefits that neither of them fully understood from the other's perspective. That was an excellent outcome. Stable, self-reinforcing, and likely to survive the operational complications of the next several hours.
He filed it.
Obito turned toward the treeline and the village walls visible through it. "I'll go in first. Get a read on the situation."
Black Zetsu had no objection. With Kamui as the infiltration method, Obito's capacity to enter and exit Konoha without detection was genuine. White Zetsu had gone ahead already and would have preliminary intelligence available. The sequencing was sound.
"Be careful," Black Zetsu said.
Obito nodded once and activated Kamui again.
Finn, standing three meters away, felt the edge of it. Not as close as before, no physical contact, the absorption was proportionally smaller. But not zero.
He watched Obito's figure dissolve into the spatial distortion with an expression that someone attentive might have called warm.
What a useful person.
He couldn't help absorbing it when Kamui operated in his proximity. That was simply how his nature currently worked around genuine space-time energy. Perhaps when he had the Flying Thunder God Technique in hand, when he'd studied the actual mechanics and developed some intentional interface with the energy, he'd be able to modulate the passive absorption rather than having it simply happen.
For now, it happened.
Obito, emerging somewhere inside Konoha's perimeter, would be noticing again that the energy cost of his second use was higher than expected and developing an explanation for it that didn't involve anything currently standing outside the village walls.
Finn looked at the place where Obito had been, then looked at the walls of Konoha rising above the treeline, and settled in to wait.