Daevas in the persian mythology were warrior-gods, gods of the martial arts, wheeling destructive forces, and caring for little less that their prowess and fame.
They were the opposite of the ethical Ahuras. Zoroaster used this classification when he separated the Indo-Iranian gods. A.G.H.
Boyce, Mary, Zoroastrians: Their Religious Beliefs and Practices, New York, Routledge, 2002, p. 11