Ultraman Story 0
Originally attacking the Land of Light with an army of monsters, they attacked seeking the Ultra Key under the Babarue's direction. However their forces were sent into retreat by Mother of Ultra's power, who erected a protective aura around the planet, seemingly at the expense of her own life. However, before that Father of Ultra was kidnapped and a message was sent to the Ultra Brothers, demanding the Ultra Key in exchange for his life.
- Alien Babarue (leader)
- Alien Borg: Alien Babarue's right hand man.
- Alien Mefilas
- Alien Nackle
- Black King
- Underlings: Lesser Alien Nackles, who do not display the same powers as their master.
- Alien Temperor
- Alien Hipporito
- Alien Guts
- Alien Zarab
- Alien Metron
- The Union is the first known instance of an Organization whose members are aliens and who seek to conquer the Earth, not protect it.
- Depending on the translation, Galactic Alliance is also a suitable name for their group.