Nazuna's father

 was one of the many humans that were killed by the kumogashira.

History
When the kumogashira begin to appear in the area, many humans, including him, are killed. His death caused his daughter Nazuna to develop a intense hatred towards all yōkai.

Manga vs. Anime

 * He does not appear in the anime. In the manga, his only appearance is a flashback of him and Nazuna in Chapter 39. The two of were apparently picking herbs when he is killed by the kumogashira.

Padre de Nazuna