The Espírito da Árvore das Eras (Sacred Tree of Ages Spirit) guards the temporal pathways linking feudal Japan and the modern era. Its physical form, the Sacred Tree of Ages, contains portals facilitating time travel between these periods. This function proves central when the spirit transports Towa Higurashi to the modern era during a childhood forest fire and later reopens the temporal tunnel for her return a decade later.

Acting as a sentinel against temporal disruptions, the spirit awakens from dormancy to warn the protagonists of Kirinmaru's ambitions to warp history and trigger the apocalyptic Degenerate Age. It identifies Kirinmaru as the primary antagonist due to his rivalry with the protagonists' grandfather, the Great Dog Demon.

During the Grim Comet crisis threatening both eras, the spirit collaborates with Akuru—the entity embodying time's flow, manifested as a pinwheel. Akuru sacrifices himself to reopen the sealed gateway within the tree, enabling the protagonists to return to the feudal era and prevent temporal collapse.

The spirit's influence empowers key artifacts, enabling Moroha's sacred arrows to channel spiritual energy effectively and supporting the acquisition of transformative weapons like the Zanseiken and Yukari no Tachikiri for confronting existential threats.

Following the Degenerate Age's resolution, the spirit maintains accessible temporal pathways, facilitating ongoing travel between eras and supporting the protagonists' new journeys.