Yui Shiromaru was the last member of the astronomy club before it dissolved, and she's best known for winning a national high school astrophotography competition back in the day. She's Nakami and Isaki's senpai, so they looked up to her when she was still active in the club scene.
These days, she owns and runs an arcade called "Betty" and lives in a small apartment right next door to it—basically running the place and living there makes for a convenient setup. She has a cousin named Kai.
Content compiled by AnimeList.moe from publicly available sources.
