Mizuha Kiryuu is Keiki's younger sister. She's extremely attached to him—the kind of sibling closeness that plays out as constant flirting, whether she's fussing over him or literally crawling into bed uninvited. Fans often note how unfiltered their dynamic is, with Mizuha basically treating her brother like her personal responsibility and comfort object combined.
Content compiled by AnimeList.moe from publicly available sources.
