Nako Oshimizu (押水 菜子, Oshimizu Nako) is one of the secondary-main characters of the series. She is a 17-year old cleaning maid and waitress who works part-time at Kissuisō. She is very shy and timid, which is shown by her actions of avoiding unnecessary social interactions. However, she is truly kind, able to see the good in everyone around her. At home she is usually a very reliable older sister, but she shuts this personality when outside her home.
She is an amazing swimmer, having swam ever since she was three. She was even called a Kappa when she was younger because of how well she swam. Despite her general lack of confidence, she does believe in her swimming abilities.
Later on in the series, Nako finds the courage to be a little more honest with herself and be more social with the staff of Kissuisō. She especially is on good terms with Minko. She, together with Ohana, Minko and Yuina are in the same high school, but in a different classroom.
- In the past, because she swam ever since she was three, Nako received the nickname of "Kappa". A Kappa is a common Japan folklore demon that looks like a green skinned human with a trutle shell, a duck bill and also a large "bold spot" which is know as the dish of the Kappa. They lurked in the rivers, played pranks on humans, and were very fast in the water so that they can escape trouble.