Kogara Sachi

Sachi is Kusanagi's childhood friend since she was five. Kusanagi saved her from a pack of stray dogs that she believed to be wolves. As thank you for that she helps him with everything from waking up to making breakfast and lunch for him to helping him study. They both started martial arts and kendo at same age which is where they've first met and was more of a rivalry between them than friendship. Their friendship started when Kusanagi saved her.