Yamato Takeshi is Takeru Yagi's best friend and kendo club rival at Izumo Academy. Adopted by the wealthy Yamato family, he grew up alongside Takeru, and both experience recurring dreams of combat with each other before the main events unfold.

When a sudden earthquake strikes, Yamato Takeshi wakes alongside Takeru and others in a parallel world – a ruined, empty version of their familiar school and town, devoid of people. He flees the school ruins with Takeru, Osu Seri, and Shiratori Asuka, discovering their town is similarly deserted. The group encounters mysterious cloaked figures who reveal they have been brought to this other world.

In this unfamiliar and dangerous realm, Yamato Takeshi joins the group's efforts to navigate their circumstances. His skills as a kendo practitioner and his deep-seated rivalry with Takeru form part of his initial characterization.