The Vegan Empire is an alien military force that attacked and destroyed Planet Fleed to expand their territory in their quest for control of the universe.
The Vegan Empire attacked the peaceful Planet Fleed to claim the planet's secret weapon, the Gattaiger, for their plans of conquest. However, both the Gattaiger and the planet's princess Maria Fleed were sent to Earth for safety. After many years, the Empire locates Earth planning to conquer the planet and find the princess to locate the weapon. However, they are met with resistance from the Mazinger Angels and the Iron Z. The Empire sent several assassins to deal with their pilots but end up unsuccessful. When Maria is captured and found to be the princess, the Empire scan's the birthmark on Maria to try and locate the weapon. However the MA find it first and use it against the Empire. The MA then make a final assault on the Empire's fortress on the moon and annihilate the armies by sacrificing the Gattaiger.