Introduced in the "Kiyohime Legend". She fell in love at first sight with the handsome monk Anchin, who requested for a single night's lodgings while on his way to a temple in Kumano.
However, upon visiting Anchin late at night, Kiyohime was bluntly rejected.
Nevertheless, Anchin promised to meet her again while on his way back from the temple in Kumano. However--

Anchin broke his promise out of fear for Kiyohime and ended up running away without meeting her.
Noticing that, Kiyohime felt into despair, grief and resentment over being betrayed, turned into a dragon and began to pursue him. Finally catching up at a temple, she burned Anchin to death while he was hiding inside a bell.

(Source: TYPE-MOON Wiki)