Sobojo and Eritategoromo

In Japanese folklore, Sobojo was a tengu king who lived on Mt Karuma as a mountain hermit and taught warriors the arts of swordsmanship and magic. He was once a human but due to excessive pride he was reborn as a tengu. Legend says that after his death, his priestly robes took on his spirit and transformed into a yokai known as eritategoromo. 

'Sojobo: King of the Tengu' - Katsukawa Shuntei

The robe sprouted eyes and a beard, and it's collar turned into a pointed nose. Not much is known about this yokai but it is believed to be related to the idea that one should always remain humble. It seems Sobojo thought he had reached enlightenment and would be reborn as a Buddha. This arrogance led to his tengu rebirth and despite his helpfulness towards warriors, he also had a dark side. 

'Eritategoromo' - Sekien Toriyama

Allegedly he ate the children who wandered too far into the forest. It is this evil nature that is likely to have attached itself to Sobojo's robe, causing it to transform into a yokai after his death. If you are curious to learn more about the different types of tengu, I have written about them here.

Utagawa Hiroshige, 1834

Yoshitoshi Tsukioka, 1886

'Tengu Sojobo teaching Minamoto no Yoshitsune the art of sword fighting'
- Japanese scroll, late Edo period