World of Darkness (闇の世界, Yami no Kuni?) is a world which is different than the World of Light (where Lum, Ataru and the others lived); it is a fearful world without the sun, and the gigantic mushrooms are grown all over the world. The native people who lived in the World of Darkness have darker skin tone and paler hair color. The only way to reach the World of Darkness is space warp through the shadows of planets.
- Pond of Light - The main and only airport of the World of Darkness, generally link from the shadow of moon.
- Hall of Wedding Ceremony - The place whereby the people of World of Darkness hold their wedding ceremony.