Usako Kurashiki works as the school nurse. She's basically the one who busted the protagonists sleeping in the observatory—which honestly sets off the whole chain of events. Once they actually form a real astronomy club, she ends up as the advisor, probably because she knows about their hideout and figures she might as well keep an eye on things.
She's got a pretty relaxed personality, and fans often note she's shown enjoying both smoking and drinking, which gives her a distinctive edge compared to your typical school staff member.
Content compiled by AnimeList.moe from publicly available sources.
