"Shikkoku ouji -dark prince-" is a original song composed by Lelele-P sung by Kagamine Len. The story centers around the titular Dark Prince(Len) and his infatuation with "Cinderella"(Rin). After she wanders into his castle, he acts gentlemenly and offers her his hand but claims he's only ensnaring her in a trap and wants to make her his property. However after she's stayed with him for a while, he grows to realizes he genuenly loves and cares for her. The full version of the song was featured on Lelele-P's albums LELELEGEND, ALLTIME LELELEDIO! and King and Joker.