Maiko Shindou is Shuichi Shindo's younger sister, approximately three to four years his junior. Introduced as a first-year student in the manga's first volume, she advances to senior status in the sequel *Gravitation EX*. She possesses a slender, petite build, closely resembling her brother with large eyes and a delicate facial structure; her hair and eyes are typically depicted as light brown in the manga art.

Her personality combines intelligence, sweetness, and modesty with high energy, haughtiness, and passion. Deeply concerned about Shuichi's ambitions compared to his laid-back nature, she adopts a driven and occasionally pushy attitude that manifests as nagging. She is a devoted fan of novelist Eiri Yuki.

Maiko plays a significant early role in the manga, primarily as the catalyst who spurs Shuichi to meet Tohma Seguchi after a Nittle Grasper concert. Her involvement lessens as the original series progresses, though she makes sporadic cameos later and in *Gravitation EX*. In anime adaptations, she is absent from the television series. Her sole anime appearance is a brief scene in the second episode of the OVA *Gravitation: Lyrics of Love*. No substantial character development or expanded background for Maiko exists in documented spin-offs, sequels, or other official media beyond these appearances.