|Greater Location:||Unknown (Showa Universe)|
|Type of Government:||Unknown|
The dark planet was originally an unknown planet of a star system, whose sun had died. Its effect reached the planet, causing almost all of its population to die. One single being of that planet embraced the darkness to survive, leading to the birth of Alien Empera. Because of the tragic incident that befell his homeworld and what he did to survive, the alien developed resentment for light, particularly the Land of Light and its inhabitants, leading to the foundation of Empera Army with the goal to wipe out all light in existence and rule the galaxy in darkness.
As of Alien Empera's demise, the citizens of Dark Planet are officially declared extinct. However, it was also revealed that he set up a contingency plan should he fail in his campaign.
- Original magazines in 1984 stated that Empera lives in a planet called Planet Empera (エンペラ星 Enpera Sei?). This was however retconned/debunked in recent materials, particularly that of Heisei Ultraman Era magazines and media, which proceed to claim it as the Dark Planet.
- In truth, an actual Planet Empera never existed and neither did its own inhabitants. The "Empera" name is simply a self proclamation to the dark ruler.
- A planet in Fireman has the same name and only has 2 shown inhabitants, Blacker and Black Satan.