Age 13
Shisui Uchiha's Kotoamatsukami is not only a highly secretive genjustu, but it´s also extremely powerful. Hence, few people know of its existence and that Shisui can use it. He can´t just trust anyone with this secret, but he knows that he wants to tell Y/n. Y/n is the person he trusts the most. The person he would sacrifice himself for. He might be young, but he knows his feelings towards his best friend.
The moon hung low in the sky as Shisui and Y/n sat by their favourite place, on top of a cliff on the outskirts of the Hidden Leaf Village from where they could watch the river flow beneath them. It was their favourite place. They trained here, shared conversations and sometimes just sat in silence beside each other. The gentle sound of flowing water provided a soothing backdrop to their conversation.
Y/na turned to Shisui. “Spit it out!” His eyes widened when he looked at her. A questioning look on his face. “What are you talking about?” She just rolled her eyes. She knew him too well and could look through his scheme. “I can sense that something is bothering you. And before you say everything is alright the crease on your forehead would disagree.”
He looked at her. She knew him well. And he knew that he could trust her. “Y/n I´m going to tell you something, and you must promise not to tell anyone. No one knows that I can do this, and it should stay that way.” She looked over at Shisui. He was acting so serious, something he usually didn´t. Y/n nodded and urged him to continue.
“I can use something called Kotoamatsukami. It´s a genjustu that can control people´s minds. But it´s so subtle that the people are not aware of it and think they´re doing things of their own will. You don´t even need to make eye contact to cast it. I did some research on some old Uchiha scrolls and it says that it can only be used every few years, the cool-down period changes depending on the shinobi. But you have to believe me Y/n I would never, NEVER, use this on you.”
To say she was speechless would be an understatement. She knew he was powerful; she had seen him on a mission, experienced his Body Flicker Technique with her own eyes, and saw what he was capable of…. But this… he was much more powerful than she had thought. And he had just told her his biggest secret. Well, the second biggest, the first being his love for her, but she doesn’t know that yet.
Y/n reached out and placed a comforting hand on Shisui's shoulder. He looked at her, eyes hopeful. "J-Just promise me that you'll use it wisely, and only when there's no other option." He immediately took the hand on his shoulder in his own and held onto it with both hands. “I promise Y/n, I´m already reluctant to use it. It just feels so wrong to manipulate someone like that. I promise I will only use it if someone dear to me is in grave danger and there´s no other way.” She believed him. Y/n always believed everything Shisui said, and he did the same.