One day, Kakashi was going to figure out how Ryouma did that, and copy it. Except that Ryouma seemed to change tactics at whim and Kakashi had had a standard no-copying rule ever since their first mission together.

Either way, it worked. Under Ryouma’s touch, Katsuko relaxed enough to stop fighting her own chakra, and the ugly seal on her stomach twisted into something completely unrecognizable. Kakashi frowned at it, trying to trace sense in the writhing loops and coils of Kaminari’s experimental jutsu. There was Lightning in there, both the village’s style and the chakra affinity. Something that looked like an inverted fire tri-point feeding the seal’s energy back into itself, making an exponential loop. The rest transcended affinities, tied into the very seat of Katsuko’s chakra. He recognized pieces: part of a gating seal, something that looked like it might have been taken from Aken Shaneo’s earlier theories of energy conversion...

Scrambling up, he went back to his bookshelf and pulled down half a dozen scrolls. Halfway back to Katskuo, he turned around and retrieved three books, dropping the lot in a heap on the table. Katsuko started, eyes flicking open to give him a mildly accusing look.

“Sorry,” he said, and turned away again, going to his weapons chest. He unlocked it and tipped the armour out, scattering shuriken and a wolf-faced mask. At the bottom, nestled between a broken tanto blade and a seal-stamped, hilted kunai, were an old med-kit and a cloth-bound book. He pulled out both and left the rest.

Both Katsuko and Ryouma were staring at him when he returned, looking oddly like mirror images of each other. Lean, badly scarred, dark-haired and dark-eyed, but Katsuko was delicate where Ryouma was rangy, and Ryouma was tanned where Katsuko was pale. Through some quirk of genetics, both of them had absurdly long eyelashes.

Kakashi tipped his head, then refocused, dropping back into a tailor's cross-legged seat. He flipped the med-kit and held it next to Katsuko’s stomach. Stitched into the bottom, Rin’s old good luck charm matched an inner ring of the seal.

He sat back, narrow-eyed, and let out a breath. “That’s insane.”

“Thanks for establishing that,” Katsuko said. “Can I pull my shirt down now? Because I’m starting to feel a breeze, here.”

Kakashi gave her a dry look. Her skin was fever-hot and had been for a while, if he had to guess. The only way she could be cold was in an ice bath, and even then she might steam it.

“The bitch who did it was kind of a homicidal maniac,” Ryouma said. “Is it fixable insane?”