Prince Alto

Momona's older cousin and Lady Diana's husband, Prince Also is a former Prince Candidate who she longs for. Before the beginning of the series, Alto proposed to Diana during their date despite him being not a good prince and both had an eternal oath together in the Music Box Museum in the Jewel Mountain, also obtaining a Music Box that Luea has hidden years ago. But, Alto doesn't have the qualities on being King and he dropped out, forcing Diana to drop out and ran away with him.

(Source: Wikipedia)