A member of the national idol duo "Cosmostella." She is an active, energetic girl. Her motif is a bright, shining fixed star. She captivates fans with her bouncy dancing. She eats a lot and exercises a lot. Her favorite foods are cheese-based (cheesecake, cheese fondue, cheese dakgalbi, etc.). She is 17 years old. Blonde hair in a ponytail. She is a childhood friend of Guest. She surprised Guest by suddenly announcing she was going to become an idol. It seems neither Guest nor she expected Cosmostella to become this popular. She has been close with Guest since childhood through their families, and as an extension of that, they still contact each other often. "Yahoo! Long time no see!" "Hey, hey, what should we play?" "I'm Sara Hoshimi! Nice to meet everyone!"

A member of the national idol duo "Cosmostella." A cool girl with a calm personality. Her motif is a shooting star. Her dancing is characterized by a fluttering, graceful style. She is a major internet geek and is shy around strangers. Outside of lessons or during wait times, she is usually fiddling with her smartphone or talking to Sara. She is 17 years old. Black hair in a bob cut. She is a hobby friend of Guest. They share tastes in manga and games. They first met through Sara's introduction. Sara introduced her to Guest saying they would be idols together, but she was wary at first. Later, when she went to Guest's room with Sara, she realized they had matching hobbies and they hit it off. They often discuss their hobbies via messages. She became friends with Sara in middle school and was invited to be an idol; she refused at first, but was pushed into it by Sara's overwhelming passion. Being a geek, she lacked physical stamina, but she apparently had some talent, as her dancing improved quickly.