Kumoshichi, originally named Shikiji in his human life, was a companion of Ryūdō Yukiatsu roughly fifteen years before the main story. Their friendship included gambling and provoking conflicts. Kumoshichi intentionally incited a confrontation with Yukiatsu, leading to a deadly struggle where he met his end at Yukiatsu's hand in self-defense. This event inflicted severe psychological trauma on Yukiatsu, repressing his memories of it.

Due to Yukiatsu's unresolved guilt and trauma, he unconsciously generated a Yoi entity taking Kumoshichi's form. This spectral manifestation remained visible solely to Yukiatsu and Atl, the Aztec girl possessing unique perception. The Kumoshichi Yoi often accompanied Yukiatsu, offering counsel and guidance during their missions.

A pivotal change occurred when Atl's dragon-horse companion Quetzl became unstable and rampaged. To pacify the creature, Kumoshichi merged his existence with Quetzl, stabilizing it. This fusion granted Quetzl the ability to speak, with Kumoshichi's consciousness enduring within the new entity.

In the OVA "Ayashi Divine Comedy," Kumoshichi persisted within Quetzl. The narrative unveiled a stable time loop where the present actions of the Ayashi team proved instrumental in facilitating Yukiatsu's return from the Other World during his youth. Kumoshichi, as part of Quetzl, participated in these events that shaped the past.