Shinobu is also the younger sister of Kanae Kocho along with her adoptive younger sister Kanao Tsuyuri. After a demon killed her parents, Shinobu joined the Demon Slayer Corps along with her sister in order to protect others from suffering the same fate as her.
Shinobu displays a bright, friendly and cheerful demeanor, always having an easygoing smile on her face regardless of the situation she is in. However, her outward behavior is shown very quickly to be a façade. This is displayed in the way she enjoys teasing others, to the point of being rather sadistic about it.