Itachi was ten when he entered his house to see Izuna playing with the Hokage son and found himself thinking how his whisker marks were cute, when he was reminded of a memory from 7 years ago, of Sarada telling him a story about Naruto, then showing him a photograph of a blonde man, with blue eyes and whisker marks on his cheeks.

Pieces began align themselves in Itachi's head and he was struck with the revelation, which previously he would have considered an impossibility.

"Fuck." he breathed out.

"You're lucky your mom isn't home, right now or she'd be washing your mouth with soap." Sarada called from the kitchen. "What happened though? I don't think I've ever heard you curse before."

"Who are you?" he asked her.

A concerned expression crossed her face. "Are you all right?" she put the back of her hand on his forehead, checking his her . "Did you hit your head?"

"Karasu is me. Sasuke is Izuna. Who are you?" he said bluntly, before she could get even more worked up.

"Damn. I owe Karasu 1000 Ryo. Couldn't you wait just a few months Itachi-kun?" she grumbled.

He looked at her pointedly.

"All right." she sighed. "Well genetically, I'm your niece."

That was what he would have guessed. Sasuke acted more paternal towards her than he did in with Karasu.

"How did this happen?" he asked.

"Your father had an accident with space time and blood seals."

"I see." he said, before walking away, trying not to think about the implications of Shisui having a crush on his older self.