She always was tired, she talked quiet and slow. She had a bad memory and loved owls. Her and Muichiro often got along together because they kinda had the same energy. Y/N had Cyro breathing and is the Cyro Hashira. She takes on lots of missions and always comes back ready for another one. And nobody really knew how dangerous Cyro breathing was. Until one day Kagaya had been reading through scrolls that give information on each breathing style ever made. When he can across Cyro breathing and read it,things started to click. How Y/N started with energy like Mitsuri but over the years lost the energy and became like Giyu and Muichiro. She physically cant sleep more than 4 hours. The users body would stay cold.