Misako Yasuda attends Matsuoka Girl's High School as a first-year student alongside classmates Fumi Manjōme, Yōko Hon'atsugi, and Miwa Motegi. She maintains a particularly close bond with Yōko and Miwa, with the trio establishing mutual nicknames; Misako is affectionately called "Yassan" within their circle.

Physically, Misako possesses thick eyebrows, striking blue eyes, and short, frizzy black hair styled in a boyish cut. She stands 1.57 meters tall. Her personality radiates high energy, positioning her as the driving force in her friend group. She actively organizes and participates in pranks and tests of courage, including ghost-story sessions and games designed to frighten others.

As an active drama club member at Matsuoka, she collaborates with Yōko and Miwa in supporting roles for school productions. This includes assisting Fujigaya Girls Academy’s drama club in their adaptation of *Wuthering Heights*, where she works alongside Fumi Manjōme—though Fumi does not join Matsuoka’s drama club. Misako’s friendships and drama club engagements define her central experiences.