On the surface the planet resembles an idyllic land of green plains, and sparkling rivers. It appears peaceful and its people simple, dressed in Greek togas, while buildings similar to the Parthenon in Greece litter the surface. However underneath the ground is advanced technology and cities.
The planet appears to be run by a ruling council of elders. How they are elected is not entirely known, if by vote, based on age, or a combination of the two. This council sits over judicial matters as they were the ones who sentenced Heller and his followers to exile. Among the council the Great Sage sits at the top as the most respected leader, and seemingly ultimate authority.
A million years ago, the people of U40 created the Ultra Mind, which gave them the power to transform from humanoids into Ultrahumanoids. They used this power to uphold peace throughout the universe, though one man and his followers decided to use their powers for conquest, abandoning their Ultrahumanoid appearances in exchange for immortality. Defeated, they were exiled to the Dark Nebula by the Great Sage. After that, the Ultra Mind was sealed away inside a hidden hole in space. The Ultras of U40 made enemies with other races such as the Bader Group, Alien Baladon and Alien Scien.
- People of U40: The average citizen of U40.
- General Warriors: The average warriors, unlike the Great Eight they do not have the power to become giants, lacking the star medals on their chests.
- Zamius: An older Ultra who commanded the Ultra's Fleet during the battle with the Bader Group. His human form has a scar over his left eye.
- Great Eight:
- Great Sage
- Ultraman Titas
- Mattia: A friend of Titas
- Former Natives: The exiled natives who wanted to turn the people of U40 into the conquerors. They have since become enemies of their former homeland.
- Although stated to be in the Milky Way galaxy, Earth's home galaxy, U40 is stated to be two million light years away. In real life the Milky Way is estimated to be 100,000 Light years in diameter, meaning that U40 would be placed close (in galactic terms) to the Milky Way's closest neighbouring galaxy, Andromeda, which is approximately 2.5 million light years from Earth.
- The people of U40 are very obviously based on common depictions of ancient Greeks, given their style of dress, and architecture.