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Kaylon 1, also Kaylon[1][2] or rarely Kaylon Prime,[3] was the homeworld of the Kaylon and the "Builder" species. Admiral Halsey stated that the planet was "a long way" from Planetary Union space.[4]


Kaylon 1 was a planet populated by artificial life-forms.[1] According to Isaac, its circumference was 57,583 kilometers with an average density of 4.42 grams per cubic centimeter and a gravity 1.13 times that of Earth.[1]

Forty meters below the surface were thousands of vast "subterranean structures" extending for miles all over the planet, a network of tunnels, chambers, and caves connected to the surface through chutes.[5] Each structure housed the corpses of the original indigenous species to the planet, known the "Builders." A single chamber contained 500,000 bodies alone.[4]

The planet was heavily guarded by a defense perimeter and highly advanced scanning technology. A sphere array was located in the southern hemisphere of the planet.[4]


Kaylon 1 was once home to an unnamed species of organic lifeforms who created the Kaylon race as servants. The Kaylon, however, soon developed sentience and, after failing to peacefully negotiate for their freedom, rebelled against their creators, utterly exterminating all organic life on the planet, burying the Builders' remains in a series of caves beneath the planet before they rebuilt their world into a perfect mechanical society.

In the 25th Century, Kaylon society had grown to a point where they had exceeded the informational capacity of their world. Needing to colonize space, the Kaylon Primary dispatched Isaac to infiltrate and observe the neighboring Planetary Union and discover if the organics were worthy of surviving or had to be eliminated.

The Kaylon were infamously isolationist. Even as late as December 2420, no human had visited Kaylon 1.[1]

In 2420, the Kaylon felt Isaac had gathered enough data and deactivated him. Unaware of this, the USS Orville brought Isaac back to Kaylon 1 to have him repaired. Seeing in the ship a way to sneak past the Union defenses, the Kaylon stalled Mercer until they were ready to take the ship, seizing it as their flagship as their invasion fleet launched. Though the Kaylon initially held the upper hand in the Battle of Earth, they retreated back home when the Krill fleet joined the fight.


In a September 2017 interview, actor Mark Jackson said that there were plans to visit the planet in Season 1 that were tabled for a potential second season.[6] This eventually came to fruition in the episodes Identity, Pt. 1 and Identity, Pt. 2.


  • Kaylon 1 was so far from Union space that it was "outside of comm range."[2]
  • In A Happy Refrain, Issac stated the planet had a circumference of 57,583 kilometers, an average density of 4.42 grams per cubic centimeter, and a gravity of 1.13 g.[1] The math, however, would place such a world's gravity as 1.15 g.
    • The density, gravity, and measurements of this planet was set by the show's science advisor André Bormanis.[7]
  • It is unclear whether Kaylon 1 was the planet's original name or one that the Kaylon bestowed upon it once they took over.