Mion is a 12-year-old girl from Ikebukuro West Gate Park. She shows up right in episode one as someone looking for help—she's the one who first brings a job to Majima Makoto and the G-Boys.
At first, Mion comes across as pretty rough around the edges, kind of standoffish. But once she realizes that Majima's crew will actually help her out, she loosens up considerably. Fans often note that her initial abrasiveness gives way to a more likeable side once she trusts the group.
Content compiled by AnimeList.moe from publicly available sources.
