The arch nemesis of the Ultra Brothers, with the ambition of conquering the universe. Alien Temperor uses various weapons and abilities, such as the Ultra Brothers Killer Beam.

The Alien Temperor plans to blow up the Land of Light, but finds out that the Ultra 6 Brothers from Zoffy to Taro are on Earth, they change their plan to attack Earth. The first Alien Temperor figures out the Ultras plan to lure the Alien Temperors to an unpopular coast-side, so remain at a city in Tokyo, defeating Taro twice, when he appeared by himself. Even on the third time, it overpowered Taro and succeeded to lure the Ultra Brothers to the city. However, thanks to Taro’s “Plan Ball”, micro-sizing himself, the first Alien Temperor was defeated.

The second Alien Temperor that appeared possessed into Saori, capturing Kotaro and defeating the Ultra Brothers disguised into ZAT members and volleyball players with its Specter Beam. In the final battle against the Ultra Brothers, the Alien Temperor did not budge with Jack and Seven’s Double beam, appearing to stand on top. At the end, it was killed with Taro’s Neo Strium Beam.