Tōtarō Yamano is the younger brother of Eiko Yamano, a Garde pilot killed and absorbed by a Gauna during Nagate Tanikaze's first combat mission. As a child, Tōtarō witnessed his sister's death and saw Tanikaze avenge it. Years later, he enlisted in the Sidonia Defense Force. During his service, he encountered Norio Kunato, who had recently recovered from mental domination by the scientist Ochiai. Approximately ten years after the Battle for Planet Nine, Tōtarō served in the Defense Force during the final Gauna conflict depicted in "Love Woven in the Stars." He belonged to a new generation of pilots emerging after a decade of relative peace following Sidonia's colonization of the Lem star system.