Raigō was a Buddhist monk who lived during the reign of Emperor Shirakawa, residing at Mii-dera. During his lifetime he was tasked by Shirakawa to pray for the safe birth of his son, with the promise of his temple being expanded if he did so.
The Emperor ultimately reneged on his promise due to Raigō’s rivals and so he went on hunger strike and died. Legend says he was then reborn as the Yōkai called Tesso, a plague of rats which went on the ravage the temple libraries of Kyoto, in particular that of Enryaku-ji.1
1. Yoda, H. and Alt, M. (2016) “Japandemonium: Illustrated: The Yokai Encyclopaedia of Toriyama Sekien.”. New York: Dover Publications, Inc.
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