Mizuki "Hatchobori" Horonushi

About

Because of the two middle characters in her name (主水), she was nicknamed Hatchobori after a certain period drama. She's always been in the same class with Hinata, and the two have been inseparable since 3rd grade. They used to stay over at each other's houses when they were little . She's an only child, so she can be selfish and a bit unaware of her surroundings, and for better or worse, she's very up-front and honest.

(Source: the manga's character introductions)