Yayoi, the second eldest among five sisters, balances dual roles as an idol singer and frontline fighter pilot in her family. Born March 7, she begins at 18 and ages to 19 as events unfold. Her tomboyish, competitive nature drives her to dominate sports meets with relentless intensity, even against siblings. Initially hesitant about idol life, she joined to avoid isolation, prioritizing family bonds. Interactions with her sisters blend bluntness and fiery clashes, particularly with the youngest, whom she disciplines with sharp physical reprimands when provoked.

As a pilot, she commands the HB-02, a heavily armed aircraft equipped with advanced vertical takeoff systems, leveraging its tactical capabilities for close-range assaults and occasional synchronized maneuvers with a sister. Off the battlefield, she transitions to the stage, delivering harmonies in duets with the eldest sister during concerts.

Her story centers on balancing combat missions with idol commitments, anchored firmly within core team dynamics. No spin-offs or extended media expand her background or progression beyond these established traits and roles.