Tobi is a prayer slip that once belonged to Rao but was given sentience by Ninetails to act as a gatekeeper to Oni Island. He is polite even when being insulted and is inscribed with four kanji meaning "mind your body; preserve your life".
Despite his post as gatekeeper Tobi’s true passion is competition through races. Although he had been challenged many times by Oni Island’s inhabitants he had not met his equal until Amaterasu. After being bested at every race Tobi admits to Amaterasu that he’s come to see her more as a friend than an enemy and wishes her luck in the ensuing battle before disintegrating after having been stripped of his life for abandoning his post. Tobi states that he died with no regrets doing the thing he loved most and leaves behind a single flower.