The Gandharvas were spirits of the air, forests, and mountains; they were the mates of the Apsaras. They are all male, and had differing descriptions. Sometimes they were seen as shaggy, damp, and dirty creatures who were part man and part animal; other times they were men with birds' legs and wings; the could be centaur-like, half man and half horse; or they sometimes were seen as fair men who had effeminate features. They were known for their musical skills, their power to cast illusions, and their skill with horses. They sometimes were the attendants of the devas, and would often combat human heroes. If the hero was victorious, the Gandharva would help the hero on his quest, but if the hero lost, he would be carried away, never to be heard from again. The Gandharvas were also the protectors of Soma, which they guarded with jealous intent.