Minamo Katsura  

, 桂 みなも

Seinas younger sister, Minamo, is known for being mischievous and full of pranks despite having a physically weak body. She hides her weakness by engaging in activities like drawing and scriptwriting. Her creativity led to projects such as creating a card game featuring the members of the student council and producing a play called "Space Alien." Despite her fragile heart, Minamo doesn't want others to feel sympathy for her, which motivates her to push herself to the brink of danger for her health.