Yuki Endō teaches at Hoshizaki High School and advises the earth sciences club, formed from merged astronomy and geology clubs. Elderly acquaintances at a hot spring hint she endured professional struggles after becoming a teacher, sparking student concern for her well-being.

Warm-hearted and open-minded, she guides students with patience and approachability. She actively supports club activities, organizing field trips like a summer camp to her grandmother’s residence near observational sites for hands-on astronomy and geology learning. During a riverside barbecue and hot springs excursion, she oversees student activities while encouraging scientific curiosity through rock collection and astronomical observation.

Her interactions reflect mutual care; after Mira Konohata overhears discussions about her past difficulties, Mira discreetly provides medicine without explanation. As advisor, Yuki consistently facilitates logistics—arranging off-campus transportation and endorsing participation in events like the astronomy-focused Shining Star Challenge. She maintains a supportive presence during routine club operations and school events, fostering academic and exploratory pursuits among members.