Seabook's little sister is an elementary school student at the Frontier IV space colony. Rees flees the colony along with her brother and finds refuge aboard the training ship Space Ark, where she immediately makes herself useful by delivering food to the ship's overworked crew. Although gentle and compassionate by nature, Rees shows stubborn determination when she's sticking up for her brother or scolding her timid "boyfriend" Bertuo Rodriguez.