Aoba's friend who runs the gang Dry Juice. He's tried to recruit Aoba but always failed. He's also a tattoo artist and owner of a tattoo parlor/bar named Black Needle.
In the anime Mizuki has an unnamed allmate which appears to be a stoat in its winter coat, so it is referred to as an ermine
The name Mizuki can translate to either "beautiful" and "moon," or "congratulations" and "hope."
Content compiled by AnimeList.moe from publicly available sources.
