Usami Mizuki is a second-year student at Tsukumori Middle School and basically runs the Art Club solo—which tells you something about her dedication. She's genuinely kind and empathetic, the type who'll help out anyone who needs it without making a big deal about it.
That said, she's got a short fuse. She's laid-back most of the time, but the moment someone acts perverted or lazy around her—especially when it comes to wasting artistic talent—she snaps. Subaru in particular gets under her skin with his whole thing of using his actual skills just to draw cute anime girls. When she's had enough, she's not afraid to get physical to shut it down, though she's not needlessly violent about it. It just happens when it needs to happen.
Content compiled by AnimeList.moe from publicly available sources.