Gagoze is a Japanese Yokai monster mentioned in books like "Nihon Genhou Zenaku Ryouiki" in 822, "Honchou Monzui" in 1060, and "Gazu Hyakki Yakou" in 1776.
Gagoze was believed to be appeared at Gangouji Temple in Nara during Asuka era 600 to 700. One day, Raijin the god of thunder in a form of child fell onto the ground with lightning near a farmer's house in Owari. A farmer came out and tried to kill it. Raijin begged the farmer for mercy and promised a birth of a strong child like Raijin if the farmer let the Raijin go. Farmer accepted and made a little boat as Raijin asked, Raijin hopped on it and flew back to the sky.
Soon after, wife of the farmer had a baby that has an enormous power and strength. At the age of 10, the child could defeat the strongest man in imperial palace for no problem.
The child became a child monk at Gangouji Temple when there was a serial murder of child monks in Gangouji Temple. It was belived to be done by a monster in the temple. The child said he's gonna catch the monster. He stayed in the bell room and waited for the monster to come. Around dawn, the monster appeared, The child captured its hair and slammed around. Soon after in the morning, the child pulled off the monster's hair and the monster ran away. The child traced the monster's blood and it led to a grave which was for a guy who used to work in the temple. The guy's spirit became the monster and caused the temple some troubles.
The child solved many problems with his power and became known as "Dojou Houshi" after he finished studying at the temple.