Chitoku Hoshi (智徳法師)
Chitoku hoshi (the Buddhist priest Chitoku) was Onmyoji (a Yin yang master) around the reign of Emperor Ichijo in the Heian period.
"Konjaku Monogatari" (Tales of Now and Then) says that he helped the ship owner attacked by pirates off the coast of Akashi, and that he captured the pirates and got back the cargoes with his skills of Yin yang.
And when Chitoku hoshi challenged ABE no Seimei to a Yin yang match, ABE no Seimei could easily chasten Chitoku hoshi by concealing Shiki gami (avatars that a Yin yang master used in its magic).
Chitoku hoshi is said to have become a pupil of ABE no Seimei, saying that all he could do was use Shiki gami, and that it was absolutely impossible for him to conceal other people's tools.