Celestialsapien

Celestialsapiens (A play on "celestial," meaning from the stars, and "sapien," a term for intelligent) is the species of Alien X from the Forge of Creation.

Appearance
Celestialsapiens are fairly simple in physical design. They are silhouette-like humanoids that can range from any size. They have white star-like dots scattered inside their body and three trident-like horns on their forehead. Their face only consists of pupil-less eyes. Celestialsapiens are also like humanoid-shaped containers full of a chunk of outer space. Celestialsapiens are huge in size, but when Ben transforms into one (Alien X), he's regularly shaped. A baby celestialsapien is the size of a human fetus, for some reason. Likely because of their powers they can be at any size they want.

Personality
They prefer their shrouded existence at The Forge of Creation, as opposed to being involved with the "petty going-ons" of the rest of the universes. Celestialsapiens might seem like they have a blank personality, judging by them being frozen, but Celestialsapiens have three personalities: the voice of rage and aggression, the voice of love and compassion, and a voice of reason. Two out of three must agree on something in order for the Celestialsapien to perform any sort of action. All three voices speak in unison when the Celestialsapien speaks, and depending on what the voices agree on, they shout either "Seconded!", or "Motion carried!" if they agree, and if they don't, they shout "Motion denied!".

Dwayne McDuffie Confirmed that Baby Celestialsapiens don't have multiple personalities.

Powers and Abilities
Celestialsapiens have a very strong ability to warp reality, meaning their thoughts can come to life. They apparently are able to alter time, space, and dimensions. Their reality warping is so powerful, that the personalities can even prevent the Celestialsapien from being destroyed just by agreeing that it won't.

Alien X
The Omnitrix's DNA sample of Celestialsapien is Alien X. A theory is when Azmuth took the Celestialsapien's DNA, he used his advanced technology to remove the voice of reason, so that it could be replaced by the wearer of the Omnitrix when they transform into Alien X. Although Azmuth could have gotten the DNA sample from a newborn Celestialsapien. Another theory is that the omnitrix and ultmatrix remove the voice of reason similar to when Omnitrix/Ultimatrix supleys NRG's suit or Ghostfreak's sun shield only instead of adding something it removes something, in this case the voice of reason.

Trivia

 * The "X" in Alien X might be a reference to the Roman numeral 10.
 * Celestialsapiens possess unlimited power, but are unable to use any of them.
 * For some reason, Aggregor preferred to absorb the powers of a baby Celestialsapien even though there were several hundred adults floating around him. This would mean the adults had too much power than even Aggregor would want. Dwayne McDuffie has stated that a baby wouldn't have a Serena and Bellicus to argue with. Here, or that the two personalities would be easily led.
 * Celestialsapiens are from The Forge of Creation; and due to their powers of warping reality, they could have forged reality itself.
 * In The Forge of Creation, it is revealed that Paradox is not allowed to go within 500 light years near them.
 * It appears that, like Ectonurite, Celestialsapiens retain their memories and personality from a single strand of DNA. This is hinted when Bellicus and Serena (two of Alien X's personalities) know about the fact that Paradox is not to go within 500 light years of any Celestialsapien. It is possible that they are all one and they are all connected, although that would open the question if Bellicus and Serena exist in all Celestialsapiens, or if there are different personalities in all of them.
 * According to Dwayne McDuffie it takes a Celestialsapien tens of thousands of years to develop.
 * According to Dwayne McDuffie CelestialSapiens also live in the Milky Way, but they're born in the Forge. http://dwaynemcduffie.com.lamphost.net/forums/viewtopic.php?f=2&t=2104&p=88023#p88023
 * In Ultimate Alien, in Alien X's transformation sequence, it is shown that inside a Celestialsapien's head (in the body, not the mind that the personalities are) is a yellowish green sphere. Could this be the brain, or the outside look of the universe of the personalities?