Shizuha Doi, a 16-year-old candidate pilot at Shimoji Island airbase, is the daughter of a professional photographer yet avoids her father's intrusive tendencies. As a primary trainee, she demonstrates studious ambition and reliability within group dynamics, often serving as a grounding influence. She functions as an automatic alarm for her roommate Mikaze Honjou, ensuring timely awakenings, and subtly tries to prevent Mikaze's classroom daydreaming—though rarely succeeding. Sharing her peers' aspiration to become a Comet Blaster and journey to space, she pursues this goal without excessive intensity. Compared to hot-headed Ayamo Nakamura and detached Karin Kikuhara, Shizuha maintains the group's most balanced temperament. Academically diligent without extremism, she holds multiple unexpected licenses and certifications beyond piloting. Her cautious nature typically avoids recklessness unless persuaded by friends like Mikaze, leading her into hazardous situations where she retains composure and clarity. During critical missions, Shizuha investigates Karin's abduction with Mikaze and Ayamo, uncovering alien "Star Seeds." She infiltrates Orbital Station 7 for Karin's rescue and pilots comet-blaster spacecraft to intercept an Earth-threatening comet. In the conflict's climax, she joins meteor interception efforts to eliminate multiple descending threats. Her background as a pilot candidate remains consistent across all installments, including the Advance Kanketsu-hen storyline.