Gagoze

In Heian-period narrative material summarized in modern references (Nihon Ryōiki / Honchō Monzui as reported), an extraordinary child born after an encounter with a thunder spirit later became an attendant at Gangō-ji. Later, attendants at Gangō-ji's bell tower began dying almost every night. The tale identifies the nightly attacker as an oni; when pursued at dawn its head hair had been torn off and the pursuers followed tracks to the grave of a ruffian manservant of the temple, whose dead spirit is said in the narrative to have appeared as a demonic being. The name 'Gagoze' thus became associated with the temple's nocturnal oni-attacker in classical accounts and with subsequent pictorial and theatrical portrayals.

Toriyama Sekien's Gazu Hyakki Yagyō and later pictorial sources depict Gagoze as an oni with the appearance of a monk. The Heian tale that is linked to the name also describes an extraordinary thunder-born child with snakes around the head and a tail at the back of the head; that specific description pertains to the child in the narrative rather than to a fixed canonical form for the temple-attacker. Kabuki and ukiyo-e representations (e.g., roles named Gagoze Akaemon) present stylized stage images that vary from textual descriptions.

Attested behaviors in the source narratives include violent nocturnal attacks on bell-tower attendants (multiple deaths reported 'almost every night'), superhuman physical strength (the thunder-born child is said to have had enormous strength, defeating a famous prince in a contest by age ten), self-concealment and nocturnal-only appearance (scholar-cited observation that the being would only appear at night and could not be inspected without approaching a light), and a narrative detail in which the fleeing attacker was found at dawn with its head hair torn off, leading pursuers to a grave identified as the spirit's origin.