Teoni

Provisional name. A demon captured by Urokodaki 47 years ago during the Keio era of the Edo period. As the provisional name suggests, it is a large, grotesque demon covered with multiple arms all over its body. It is sealed in the "Fuji Kasane Mountain," the site of the final trial, where it has stubbornly survived and devoured 50 humans. It harbors a deep hatred for Urokodaki, who captured it, and has killed 13 of his disciples, using the fox masks he carved as a marker. Its neck, which is its weakness, is particularly hard due to the many arms wrapped around it, so much so that when Sabito tried to cut it, his sword broke instead. However, it was no match for Tanjirou, who had also defeated other demons in the mountains, and was defeated by the "First Form: Water Surface Slash." At the moment of its demise, it remembered its human days spent with its brother, shedding tears as it disappeared.

In the anime theatrical special, it appears as the boss enemy. Additionally, it utters the line, "The era has changed from Meiji to Taisho," which became a topic of discussion as it coincided with the broadcasting period of the TV anime and the change of eras from Heisei to Reiwa, leading to the merchandising of this character.