Amami Tomonaga, mother of Yuuta, Azuki, and Kurumi, balances her career as a government archaeologist with her intermittent family life. Collaborating closely with her husband, Yuuichirou Tomonaga, she embarks on frequent expeditions—such as a prolonged dig on Hedro Island—leaving her children under Azuki’s care. Though often absent, she and Yuuichirou prioritize reconnecting with their children during brief returns to Japan before departing on new assignments.

Her prolonged absences inadvertently strain relationships at home, notably triggering jealousy in Deckerd, the sentient police robot, who feels excluded during one such visit. When Deckerd vanishes while pursuing a case alone, Amami joins the search to locate him. She fiercely protects the robot, confronting criminals who target him and affirming his place within the Tomonaga family. These actions underscore her capacity to embrace non-human entities as kin.

Her involvement beyond the primary series remains undocumented, with her narrative firmly centered on her dual identity as a driven archaeologist and a sporadically present yet devoted parent. Her background remains unchanged across documented media, emphasizing her unwavering dedication to both profession and family without expansion in supplementary materials.