A tomboyish martial arts instructor who trains Mairu and Kururi Orihara at Rakuei gym. She's built a reputation as a caring but no-nonsense teacher, and her students clearly respect her—the Orihara sisters are considered her best work.
Mikage's got the fighting chops to back up her teaching credentials. She's been doing martial arts since childhood and is genuinely dangerous in a fight, with the physical conditioning to prove it.
She and Izaya Orihara go way back to high school, where she was one of his many hangers-on. He apparently took advantage of her martial arts skills for his own schemes, and she developed feelings for him during that time. She tried to get closer to him, but nothing came of it. Things got messy enough that she eventually dropped out of school after taking the fall for one of his plans—the specifics are unclear, but it was enough to make her leave. That's when she got serious about martial arts and ended up at the gym full-time.
By the time of the series, she's moved past any romantic attachment. When Kine pressed her on how she actually felt about Izaya, she was straightforward: no love there anymore, but she does feel drawn to him. She knows logically that keeping her distance would be smarter, but admits it's harder than it sounds. Despite everything, she respects him enough to stay loyal, making her one of his more reliable allies by the end.
Content compiled by AnimeList.moe from publicly available sources.