Troubadour

From OMGWiki

Troubadour is a spirit, and, more interestingly, Urd's ex. When we first see him in the manga in Love Potion No. 9, he is described as a Cherry Tree Spirit, who must leave Urd to quest for the Golden Peach. When he reappears in "Jealous Love", he is described as a Plum Tree Spirit who apparently left Urd to search for the Golden Nightingale. He comes to the Temple Tarikihongan "to get back with Urd" but it is later revealed that in order to obtain the Golden Nightingale he need a goddess' tear. He is very jealous when it comes to Urd and shows no mercy to people that hit on her. When he found out that Keiichi was living with Urd, he tried to fill K with bugs and make him explode, but was saved by Urd. He is talented in singing and plays a harp like instrument. He forgets that he can't fly, but at the end of "Jealous Love", we see him flying off, so...I don't know.

Based on the manga, the TV series had a different story, at least the part with Keiichi being a girl.