Shio Koube

A estimated 5-7 year old girl who lives with Satou, she cares and loves Satou and enjoys bathing and sleeping with her, she is not allowed outside for any reason as she was told it is dangerous.
She is seen wearing a Light blue sailor suit and skirt.
She is willing to kiss, love and Hug Satou if she experiences a Bitter feeling.

There is a high possibility that she was kidnapped by Satou and is unaware of that fact

(Source: Happy Sugar Life)