Mytho was once a heroic and kind Prince who protected the helpless, yet in one of his many battles he encountered a raven. The only way to defeat the monster was to shatter his heart to seal it away. In doing so, he lost all emotions and was left rather lifeless.

During the beginning of the series, Mytho is dependent on Fakir for his well-being and care---the two have been friends since youth. He is also Rue's boyfriend, but whether by command or because he bluntly doesn't know better is never quite understood. When Princess Tutu first appears to him he finds that gaining back his heart is terribly painful. However, before long he is gracious to the Princess for aiding him and falls in love with her grace.