Father (King of the Oni), Mother (Queen, doesn't speak any earth language), Ten (Cousin, flies around and breathes fire a lot)
Background Info
Lum is a Princess of the Oni people. In a game of tag with a random human male for the fate of earth, she mistakenly assumes that Ataru asks her to marry him -- Which ends in a TV series spanning 196 parts, 6 movies and 6 OVAs, and countless manga.