Sleeping Princess (ねむり姫, Nemuri Hime) is a diamond that was kept in the Devil's Castle.
The demon Lucifer wants to use this diamond to power a cannon in his Devil's Castle in order to destroy the Sun. Unaware of the fact that the Sleeping Princess is a jewel, Master Roshi sends Goku and Krillin to retrieve it, thinking it is a pretty girl.
Video Game Appearance
The Sleeping Princess and the events of the film in which it appears are mentioned in a Dragon Ball History entry in Dragon Ball Fusions.