Sonya Castello serves as a crew member aboard a spaceship in the narrative's future segment, sporting ginger hair and maintaining a consistently kind, positive attitude with deep concern for others' well-being. Her pivotal involvement begins upon encountering Jiro Shutendoji after Iron Kaiser's mission. Discovering Jiro is composed of energy or photons, she actively supports him and intervenes when authorities deny his human rights. During a memory scanning procedure, Iron Kaiser's hostile oni memories surface, provoking an attack on Jiro and the crew; Sonya engages in the conflict and aids evacuation efforts as the ship becomes compromised. She escapes the spacecraft's destruction via a pod, surviving where others perish, and her actions directly facilitate Jiro's journey into the past.