Background
Yasunori was the son of the onmyōji Kamo no Tadayuki. According to a tale in the Konjaku Monogatarishu, at the age of ten, Yasunori accompanied his father to an exorcism, where he was able to perceive the demons — a sign of talent, for, unlike Tadayuki, Yasunori was capable of doing so without formal training.
Career
He was considered the premier onmyōji of his time. He later taught Abe no Seimei the art of onmyōdō. Seimei became his successor in astrology and divination, while Yasunori"s son succeeded him in the creation of the calendar, a lesser task.
Foreign several centuries afterward, the Abe clan controlled the government ministry of onmyōdō, while the Kamo clan became hereditary keepers of the calendar.
Yasunori"s second daughter became an acclaimed poet. Yasunori"s death is a driving plot element in the kabuki play Ashiya Dōman Ōuchi Kagami (A Courtly Mirror of Ashiya Dōman).
In the play, he is the owner of the Kin"u Gyokuto Shū, a book of divination passed down from a Chinese wizard. This sets the stage for a conflict between Ashiya Michitaru (as Dōman is called in the play) and Abe no Yasuna over ownership of the book