Kikyo had built the maze herself.
It occupied the lower training grounds of Kukuroo Mountain, a layered arrangement of Nen constructs that she had put considerable thought into, because the point was not to stop Killua, the point was to see exactly how he stopped being stopped. She stood at the exit arch and waited with her viewing apparatus active, the display lenses cycling through threat indicators, and watched the maze be taken apart from the inside.
The electrical discharge moved through the passages the way current moves through water: instantly, completely, without asking the maze's permission about anything. By the time she registered the sound, Killua was already at the exit with Alluka under one arm and Nanika under the other, his white hair standing in every direction, a few wisps of ozone trailing him through the arch.
Kikyo's lenses went dark. She took them off. Her eyes were already wet.
"You've really grown up," she said, in a voice that was doing its best to maintain composure and not entirely managing it. "Your mother is very happy."
Killua looked at her with the expression he used when he was genuinely moved and genuinely trying not to show it. "Okay. Don't cry."
She cried anyway.
The ability was called Friendship Lasts Forever, and it had been possible because of what Liam had done.
When Liam had used the natural system to open the channels in Alluka and Nanika, something in the specific architecture of their shared existence had responded to the opening. The YouAreNotAlone Nen beast that had been protecting Alluka since childhood, the deep accumulated wish of parents who had loved their child from beyond death, had found a new form to express itself in. Instead of simply standing between Alluka and danger, it had given both sisters a way to stand beside each other.
The mechanics were straightforward. Two bodies. Two consciousnesses. The ability maintained one as a physical double of the other at any distance, without aura cost, and the two could exchange at any time. The double looked identical to the original in every visible detail. It had no independent special abilities of its own, but it was real: solid, warm, functionally present.
Silva had thought about this for some time before announcing his position.
He called Killua to the eastern hall and stood with his arms folded and his expression in the specific configuration that meant he had made a decision and was delivering it, not opening it for discussion.
"The rule is this," he said. "At all times, one of them must keep her actual body on the estate. The double can go anywhere. The consciousness can swap freely. But the real body stays home." He held Killua's gaze. "This is not negotiable."
Killua wanted to argue and looked at his father and calculated his chances and decided against it. "If the real body is home and the double gets into trouble, can the double just... dissolve?"
"Yes. The double can be dismissed at any time. Whatever is in it at that moment simply returns."
"And if it's the consciousness that's in the double when it gets dismissed?"
"The consciousness returns to the real body. The physical experience is lost. The memories are not."
Killua thought about this. It was, when he considered it honestly, a compromise he could work with. Silva had the information he needed to understand why this rule existed and also knew better than to argue about things that Silva had already decided.
"Okay," he said.
Silva bit his thumb and held it out.
Killua looked at his father's extended hand for a moment. Then he bit his own thumb and pressed it to Silva's.
The deal was made.
Illumi was leaning against the wall of the corridor when Killua came out of the hall. He had the quality of someone who had been there for a while and had not intended to be noticed for most of it.
"So," he said. "Time to choose."
Killua looked at him.
"Who goes out first," Illumi said. "Alluka's real body, with Nanika at home. Or Nanika's real body, with Alluka at home." His eyes were the same as they always were, which was to say they communicated very little except that they were observing everything. "It's a meaningful choice."
"I'm aware."
"I'm just noting it."
"Noted. Good talk."
Killua found Alluka and Nanika in the small courtyard where they had been waiting, seated together on the same bench with the quality of people who have been sitting in the same spot for long enough to have given it some personality. They both looked up when he came in.
"Okay," he said. "Let's play a game."
Ten minutes later, Killua and Alluka walked down the mountain road toward the bus station. The morning air had the clean, cold quality that Kukuroo Mountain always had this time of year, which Killua had spent most of his life being unable to leave to compare to anywhere else.
Alluka had a map and was pointing at things on it with the focused enthusiasm of someone who had been in the same building for years and was now holding geographic data about the outside world and finding it very good.
Killua had his hands in his pockets.
"Liam said something, a while back," he said. "About an island. He said there was someone there who could be a friend. Said it like he was certain about it."
"Brother's friend?" Alluka looked up from the map with immediately increased interest. "Where? Which island?"
"That's the problem. He said Whale Island, or Shark Island, or something like that. There are about a dozen places with names like that."
"Then we go to all of them."
Killua looked at her. "That's what you took away from that."
"If the person is there, we'll find them. If they're not there, we'll have seen twelve islands." Alluka's logic had the unassailable quality of someone who considered both outcomes acceptable. "Either way."
Killua thought about this.
"Yeah," he said. "Okay."
"Let's go!"
They went to all of them.
Several were uninhabited. One had a fishing outpost and a population of eleven people and a dog. One was technically a sandbar at high tide. None of them contained anyone that Killua could identify as the specific kind of person Liam had been describing, which was, admittedly, a vague brief.
Liam had said: someone who will be a good friend to you.
The criteria for that were not obviously reflected in any particular island's population density.
Killua crossed destinations off the list without excessive disappointment. The actual point of the trip was to take Alluka somewhere, anywhere, outside the estate walls. Every crossed-off location was still somewhere she had been that was not a room on Kukuroo Mountain. That counted for something.
They found the restaurant by accident.
It was in a small coastal town, the sort of town that existed because fishing required infrastructure and infrastructure accumulated people. The restaurant had a sign. The sign said: Whale Island.
Killua stood in front of it.
"It's just the name of the restaurant," he said.
"Maybe the owner has a reason," Alluka said. "Let's go in."
"That's not a reason to—"
"Let's go in."
They went in.
The restaurant was modest and clean and had the specific smell of a place that had been serving the same reliable food for a long time and had no particular interest in changing the formula. They found a table. A waiter brought menus. Alluka seized hers with both hands and studied it with the intensity she brought to things she had not previously had access to.
Killua checked the time.
"Three hours," Alluka said, before he could say anything. "The next three hours belong to Nanika. It was a deal."
"We haven't even ordered yet. Ten minutes won't—"
"It won't!" Alluka put the menu down and looked at him very seriously. "Nanika's time is Nanika's time. Not a minute shorter. We made a deal."
Killua looked at his sister. She was right. He had made the deal.
"Okay," he said. "Swap."
Alluka's expression changed.
It was not a slow change. The specific quality of attention in her eyes shifted first, and then the set of her features adjusted by some increment that was difficult to quantify but immediately visible. The darkness that gathered in her eyes and at the corners of her mouth was not menacing in the way of something that intended harm. It was simply other, the way deep water is other from shallow water.
The waiter who had been approaching with the food cart stopped.
He stood there for a moment, holding the handle of the cart, looking at the girl across the restaurant whose face had just become a different face than the one he had been walking toward.
Nanika turned her head and looked at the menu, and then at the waiter, and then at Killua.
Killua raised a hand to the waiter in the universal gesture for it's fine, please keep coming.
The waiter kept coming, with the careful deliberateness of someone who had decided to collect more information before forming a final position on what was happening.