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We're the most powerful being in the universe. We change the very nature of space and time.


Alien X is the Omnitrix's DNA sample of a Celestialsapien from the Forge of Creation.


Alien X is a humanoid alien whose entire body is solid black, excluding his hands, which are white. He has tiny white star-like spots all over his body, giving him the appearance of a starry night sky. His eyes are green and lack pupils, and his forehead bears three horn-like protrusions.

In Omniverse, Alien X is largely the same as before, but with minor changes. His chin is now bigger, his body is more muscular, his horns are smaller, and the stars on his body are brighter than before.

Alien X wears the original Omnitrix/Ultimatrix/Omnitrix symbol on his chest.


Bellicus, Serena, and Ben, the three personalities of Alien X

Alien X has three personalities: Serena, the "voice of love and compassion", Bellicus, the "voice of rage and aggression", and Ben, the "voice of reason".[1] All three of these voices combine to form Alien X's speech. Otherwise, Alien X is silent. The only things he will say are what he will be doing - what Ben, Bellicus, and Serena have agreed to do.

As Serena and Bellicus have been arguing for eternity and before they had no tiebreaker, getting them to focus on any present task is difficult at best. This leaves Alien X's body trapped in place, floating about a foot above the ground until an agreement is made.

Powers and Abilities

Alien X is omnipotent,[note 1] being able to warp reality, time, and space with ease and at any level he wishes. Even his thoughts can become real. In short, Alien X can do anything.[2][3]

Alien X can create and recreate an entire universe at will.[4]

Alien X possesses superhuman strength and is skilled at hand-to-hand combat.[5]

Alien X is nearly invulnerable, as he was completely unharmed when the Annihilargh destroyed the universe around him.[4][note 2]

Alien X can create time waves to reverse events in a specific area[1] and black holes to suck in other beings such as another Celestialsapien.[5]

Alien X can self-duplicate and fly at high speeds.[5]

Due to the nature of his species' creation, Alien X can survive in the vacuum of space.[5]

Alien X possesses telekinesis and is capable of deflecting energy attacks, such as those generated by a Prypiatosian-B.[6]

Alien X possesses X-ray vision, meaning he can see through objects such as a mountain.[DJW 1]

Alien X can survive a timeline destruction.[DR 1]

Alien X can regenerate his limbs should they be severed,[DJW 1] as demonstrated by the Galactic Gladiator.[5]

Alien X has the ability to shapeshift, teleport and grow to a gigantic size; these feats were also demonstrated by the Galactic Gladiator.[5]


In order for Alien X to perform any action, including simple movement and transforming back, all three of his personalities must agree to do so.[note 3] This has proven to be a major weakness, as Serena and Bellicus were not interested in dealing with present affairs and wanted to finish past ones that were not possible to deal with without Ben.[note 4] In Omniverse, Ben still needs to consult Bellicus and Serena to get control, he is just better at it now.[DJW 2][DJW 3]

Alien X is vulnerable to having his omnipotent powers absorbed by Osmosians[2][3] and entities with similar powers such as Darkstar.[8][9][note 5]

Alien X's actions onto reality can be neutralized and reversed by the intervention of other Celestialsapiens.[5][MoA 1]

The weaknesses mentioned ahead are "Word of God" statements, which have not been seen on the show and may not necessarily be canon. Secondly, these are only applicable if Alien X is too slow to react due to deliberations by the personalities. Therefore, Alien X can protect himself from these weaknesses using his powers, provided he uses them.

Alien X can be devoured by a Gourmand, who would either digest him or spit him back out.[DJW 4]

Alien X can be affected by a Nemuina's sleeping dust.[DJW 5]

Alien X's personalities can be scared by Toepick's species.[DJW 6]

Alien X's life force can be drained by a Vladat.[DJW 7] He also cannot survive on Anur Vladias.[DJW 8]

Alien X's powers may either be limited to the basic cosmic laws of other universes or may not work depending on the universe.[DJW 9]

Alien X cannot manipulate mana directly because he would first have to alter the universe to change the nature of mana.[MW 1]

Alien X's cosmic powers do not work well against magic and a magic spell could cancel his omnipotence.[DJW 10][DJW 11]


Alien Force

  • Alien X first appeared in X = Ben + 2, where he stopped a flood caused by a broken dam. After much fruitless arguing, Ben convinces Serena and Bellicus to transform him into another alien (mostly by insulting them). Ben swore that he won't use Alien X again, as it is not worth the price.

Ultimate Alien


Alternate Timeline

  • In Ben 10,000 Returns, Negative Alien X was mentioned by Professor Paradox when speaking of an alternate timeline in which Albedo turned into said transformation and was trapped motionless for nearly a year.


Season 1

Season 2
Season 3

Season 1
Season 6
Season 8
Season 8

Video Games

Ben 10 Alien Force: Vilgax Attacks

Alien X appears in the game, but only in the cutscenes for the Xbox 360, Wii, PS2, and PSP versions. He is not a playable alien, being replaced by Cannonbolt or Murk Upchuck in the DS version.

Project Exonaut

Alien X is a playable Exosuit of the Atlas Brigade on Project Exonaut. He is available for purchase at level 20 for 1000 coins. His Weapon Mod, similar to Ultimate Swampfire's, decreases the Marksman's clips to three shots, but greatly increases the firing rate, speed, accuracy, and damage.

Naming and Translations

Language Name Origin
Albanian Alien X From the original English name
Arabic الفضائي اكس Alfadaaiy Ax/Alfadae Iks, Alien X
Bulgarian Извънземно Хикс From Извънземно, alien and Хикс, the Bulgarian pronunciation of letter X
Burmese All-knowing
Chinese X超人 From X and 超人 (Chāo Rén), Superman
French Alien X From the original name
German Alien X From the original name
Greek Εξωγήνος Χ From Εξωγήνος, alien. Pronounced as eksoginos
Hungarian X lény From X, and lény, creature
Italian Alienics From alien and ics, the Italian pronunciation of letter X
Polish Obcy X From obcy, alien, and X
Portuguese (Br) Alien X From the original name
Romanian Extraterestrul X From extraterestru, alien, and X
Russian Герой Х
Супергерой Икс
Икс Герой
From герой/geroy, hero and X
From cупергерой/supergeroy, superhero and X
From cупергерой/supergeroy, superhero and X
Serbian Ванземаљац Икс/Vanzemaljac Iks From ванземаљац/Vanzemaljac, alien, and Iks, the Serbian pronunciation of letter X
Spanish (HA) Alien X
Alienígena X
Extraterrestre X (Universe vs. Tennyson and Weapon XI: Part 1)
From the original name; pronounced /'alɪɛn 'ɛkɪs/.
From alienígena, alien and X.
From extraterrestre, extraterrestrial and X.
Spanish (Spain) Alien X From the original name
Swedish Alien X From the original name
Turkish Uzaylı X from Alien X


Alien X's name is made up of "alien", a reference to him being an extraterrestrial life form, as well as a transformation, and "X", the roman numeral for 10, which refers to both his mysteriousness and the fact that he is Ben's tenth alien in Alien Force. "X" is also used as an unknown variable, which references how Alien X's appearance and powers were kept secret until his debut.


  • Ben, Azmuth, and Professor Paradox all acknowledge that Alien X is the most powerful being in the Omnitrix.[3][note 6]
    • However, Ben has conceded that transforming into Alien X is not worth the cost, as the risk is simply too great for him to use the transformation.[1][merch 1] Simply put, Alien X is too much of a pain for Ben to use unless there is no other option.[DJW 12]
  • Alien X's starred body is not simply "aesthetic". Like all Celestialsapiens, Alien X contains his own "debate dimension", which exists inside his head.[DM 2] But rather than being a real place, it is a visual interpretation of what is happening mentally.[DJW 13]
    • This explains how Paradox was able to travel inside Alien X and speak to Ben whilst he was arguing with Serena and Bellicus before reversing the transformation.[3]
  • Much like his birthplace, Alien X exists outside the universe (i.e. time and space). Beings existing outside time and space are simultaneously everywhere and nowhere at the same time.[DR 2]
    • This also implies that since Ben Prime and Ben 10,000 share the same Celestialsapien DNA in their Omnitrices, the Alien X transformation used by them is the same Alien X, not just genetically, but literally.[DR 2]
  • Sometime between the events of The Final Battle: Part 2 and The Forge of Creation, Ben had had the Ultimatrix modified to lock the Alien X transformation, to both prevent himself from accidentally transforming into him and as a safety measure to keep someone like Albedo from using it. The only way to access Alien X was to use a pair of keys in Gwen and Kevin's possession. This is not the case for the new Omnitrix, in which Alien X is accessible without any keys, as the threat of Albedo turning into Alien X has been neutralized.[note 7]
  • In Universe vs. Tennyson, Ben offers to let the two personalities argue between themselves for eternity if they give him full control over Alien X. Serena agrees, followed by an initially reluctant Bellicus, giving Ben full control over Alien X. This is seen again in Weapon XI: Part 1.
  • Albedo's Bellicus and Serena would appear red.[DJW 16]
  • In A Jolt from the Past, Rook speaks of Alien X, but believes he is just a rumor. Ben tries to convince him that Alien X is real, but Rook doesn't believe him and asks Ben to transform and show him, which Ben refused.
    • This conversation happens again in So Long, and Thanks for All the Smoothies, and by the end of the episode, Rook sees Alien X for real, but after the universe is restored by Ben, his memory of Alien X no longer remains and he disbelieves Ben when the latter says that he used Alien X to recreate the Universe.
    • Finally, on seeing Celestialsapiens and Alien X in Universe vs. Tennyson, Rook believes Ben.
  • In Andreas' Fault, a fan of Ben refers to the Alien X smoothie as a disappointment as well as saying it tastes like "filler". This is a reference to Alien X's constant standing in the series.
  • In many promotional images and the openings to Alien Force and Ultimate Alien, Alien X is posing dramatically. This ironic, considering that he is frozen in a standing-up position for most of the time in the series proper.
  • Alien X had concept art drawn by Eric Canete,[EC 1] whereas his final design was created by Glenn Wong, with color styling by Chris Hooten.[GW 1]
  • The original plan for Alien X had him with two faces talking to represent two personalities in one body. However, because of animation challenges and the fact that Alien X has one male and one female personality, which was not reflected by the faces, the idea was scrapped.[GM 1]
  • Alien X was the first alien featured in Alien Force and Ultimate Alien to not be voiced by Dee Bradley Baker; the second being Rath.
  • During the entirety of Season 1 of Alien Force, the opening of the show only displayed a silhouette of Alien X because he was meant to be a surprise alien. However, part of his face could be seen on the bottom right of the screen. From Season 2 onwards, the intro began showing Alien X's full image.
  • Alien X is a Nano and a former NPC in the game FusionFall.
  • In Project Exonaut, Alien X is a level 10 suit.


  1. 1.0 1.1 There has been much debate between fans as to if Alien X (and Celestialsapiens by extension) is to be considered omnipotent or nigh-omnipotent. Given that literally any thought of Alien X can be converted to reality, by definition Alien X is all-powerful and thus is omnipotent. While his physical form does have weaknesses, they can be eliminated at any moment by a resolution of his personalities. His actions being reverted by other Celestialsapiens, and him being harmed because of the time it takes for the personalities to agree to defend themselves is a practical limitation on Alien X. In theory, he has all possible power, as there is no thought that cannot be converted into reality. Yet, due to the aforementioned limitations, some fans consider him to be nigh-omnipotent. The discretion is left to the reader to decide which category to put Alien X in.
  2. This is because the Annihilargh affected only the universe. As for Celestialsapiens, rather than being born out of the universe, they are entities separate from it.[3]
  3. In Alien Force and Ultimate Alien, Ben served as the tiebreaker for Alien X's personalities. If two of the personalities agreed on something, the motion was carried. This has been altered in Omniverse, as all three personalities must agree.
  4. This weakness was referenced by Professor Paradox, when he revealed that there is an alternate timeline where Albedo transformed into Negative Alien X and was stuck motionless for nearly a year.[7]
  5. This was in fact Aggregor's master plan: he collected the powers of 5 aliens from the Andromeda Galaxy (i.e.Galapagus, Bivalvan, Andreas, Ra'ad, P'andor) to obtain the Map of Infinity, which he used to gain access to the Forge of Creation, so he could absorb the powers of a newborn Celestialsapien.[3]
  6. Originally, Dwayne McDuffie believed that Alien X was not the most powerful alien in the Omnitrix.[DM 1] This has been retconned in Ultimate Alien, where it is revealed that Celestialsapiens possess the greatest power in the universe.[3]
  7. This is because Albedo could transform into aliens that Ben had unlocked in the Ultimatrix prior to Double or Nothing,[DJW 14][DJW 15] which does not include Alien X.


Crew Statements

Derrick J. Wyatt

Man of Action

Duncan Rouleau

Matt Wayne

Eric Canete

Glenn Wong

Glen Murakami

Dwayne McDuffie


See Also

Introduced in Ben 10 ArctiguanaBlitzwolferBuzzshockCannonboltDiamondheadDittoEye GuyFour ArmsFrankenstrikeGhostfreakGrey MatterHeatblastRipjawsSnare-ohSpitterStinkflyUpchuckUpgradeWay BigWildmuttWildvineXLR8
Introduced in Alien Force Alien XBig ChillBrainstormChromastoneEcho EchoGoopHumungousaurJetrayLodestarNanomechRathSpidermonkeySwampfire
Introduced in Ultimate Alien AmpfibianArmodrilloChamalienClockworkEatleFasttrackJuryriggNRGShocksquatchTerraspinWater Hazard
Introduced in Omniverse AstrodactylAtomixBall WeevilBloxxBullfragCrashhopperFeedbackGravattackGutrotKickin HawkMole-StachePesky DustThe WorstToepickWalkatroutWhampire
Future Aliens SandboxShellheadSnakepit
Ultimate Aliens AlbedoArctiguanaBenBig ChillCannonboltEcho EchoGravattackHumungousaurRathSpidermonkeySwampfireWay BigWildmutt
Fusion Aliens Atomic-XBig ChuckCrashockerDiamond MatterFourmungousaurHeat JawsHumungoopsaurStink ArmsUprigg
Concept Fusion Aliens GravadactylXLRG
Other Aliens in Official Media 10/10/10 Box AliensAntigraviteslaBob the BlobCartoon Network AlienEon (Retconned)MoyoInvinciblePlantapocalypsePortalerRocksShadowmanSquidstrictorStretcheleo