Masaki is the main female protagonist of Mayoiga and one of the 30 individuals aboard the bus to Nanakimura. She is a 17-year-old student with a bright and earnest personality, but has a slight dislike of mysterious young ladies.

Masaki is a strange girl who believes in what she thinks. It's implied that Masaki may have an odd ability to see or sense things in the future, though this has never been directly seen in the episodes. She's very emotional and has random outbursts from time to time, even asking Mitsumune if she was "off her rocker" in episode 1. She also has motion sickness.