How powerful is Alien X?
Alien X belongs to the Celestial sapient race, which as we know are essentially the highest lifeforms in the Ben 10 omniverse.
Alien X is connected to the omnitrix, an alien device that stuck itself upon Ben Tennyson’s wrist (now he’s got superpowers, he’s no ordinary kid) and can even prevent the time limit if it occurs. Alien X exists outside of the multiverse when not in use, and is described as omnipresent in this time, since he is “everywhere and nowhere at the same time” according to author statements.
Alien X was seen moving quadrillions of times faster than light, seeing that he moved fast enough to create a black hole. Alien X lives in the forge of creation outside of time, meaning he has at least infinite speed.
Alien X has many abilities that makes him very difficult to kill, such as regeneration, teleportation, mind control, immense strength, seemingly unlimited stamina, size enhancement, duplication, shape shifting, combat skill, fire manipulation, flight, timeline travel, gravity manipulation, energy deflection, forcefield creation, portal creation, time reversal, creation, erasure, self-sustenance, near-invulnerability, and more, as is entailed below.
Alien X is a prominent reality warper, being able to create and erase space-time, as well as making his thoughts realities. Serena explains to Ben that Alien X changes the very nature of space and time.
Alien X was able to survive the destruction of the universe, move within the timeless void that remained, and create a new universe, be it with minor changes. From this we can deduct that Alien X has nigh-omniscience, as he was able to create nearly everything, even things and people he had no knowledge of. Alien X is in himself a pocket reality with 3 personalities (Serena, Bellicus and of course Ben) that throughout the show have been able to better agree on decisions, like giving Ben control of Alien X.
Alien X was described by paradox (a being outside of time) as omnipotent and by Azmuth (an intergalactic super genius) as the greatest force in the universe. Azmuth claims he can do anything as well.
While Alien X is not omnipotent in the sense of having no weaknesses, he has shown by statements and feats to be the strongest species in the Ben 10 verse. In this sense, he does fit the “all-powerful” definition of omnipotent, since he is a great deal of power above anything in the omniverse.
While X was listed a few weaknesses by the creators, the statements may or may not be canon (official). He would never usually have those weaknesses (for example, being eaten by a Gourmand) due to his power and the ability to negate others abilities (for example, being able to move away fast enough, or being able to defeat the Gourmand in time). (Gourmand=Upchuck’s species)
He would scale above the annilargh, which he tanked the destruction of the universe from. He would scale above the Chronosapien Time Bomb, which destroyed “all timelines except one” that are “infinitely branching”. Quantum Physics, which Paradox mentions Ben should brush up on while explaining the structure of the omniverse, confirms the multiverse of Ben 10 to be infinite, for further clarification. An author confirmed he could survive timeline destruction, and in another statement it is said that Alien X did not save the timelines because it would have no effect on him.
The Q&A states a celestial sapient could not survive timeline/omniversal destruction on their own, but they mention other things in that thread which are not canon to the show such as Anur Vladias, so it is possible they are referencing non-canon material such as comics or video games, but it this thread seems unreliable for that reason.
Celestial sapiens are responsible for the changes of the art style, as we see before the Galactic Gladiator match. This could be a multiversal feat in itself, or it could be a special ability. This could be described as physics manipulation because it changed the realism of the graphics, down to saturation of color, meaning celestials could manipulate physics equations like Planck’s constant to manipulate fundamental forces like light and energy, or change the laws of conservation/gravity for the cartoon-like effects we see in and out of omniverse. It has the potential to be very threatening regardless.
Celestial sapiens created the Multiverse Preservation Act, which were rules against creating universes. An author statement shows that Celestial sapiens can change the laws of magic as well, so it is possible that they can manipulate other fundamental forces through making these laws. Starbeard, another celestialsapien, was able to sense the universe being destroyed (from the forge most likely), so they may have the ability of cosmic awareness.
He would scale above the Contumelia, who are described as fifth dimensional, who described their force field as “extra dimensional” in the context that it is impossible to breach by them, who are extra-dimensional by definition. A celestial arm, constructed by Skurd (A DNA-absorbing symbiotic creature) was able to breach this field. Keep in mind that this was only a fraction of his power because it was not connecting to his mind, where his reality warping powers would logically stem from, and it is just one limb of his body. This would, at bare minimum, put Alien X 2 degrees above the baseline for universal+ because he can cut through a barrier that held back a device which can destroy and create timelines, depending on the space it is launched in. Based on the context, it could put him at a 5 or 6-dimensional being. The creators confirmed Alien X to be above Contumelia as well.
He would scale above the Naljians, who are 26 dimensional, who also describe the dimension Ben lives in as a “lower dimension.” Keep in mind paradox would likely be able to know about extra-dimensional characters as he navigates the multiverse outside of time. There are likely 26 dimensions in Ben 10 due to string theory existing, as confirmed by paradox when he was explaining the concept of timelines to Ben before the events of the Chronosapien Time Bomb.
He would scale above the Chrono Navigator, which is said by paradox to be able to destroy all existence, which could now mean 26 dimensions from what we know of the cosmology, or it could mean all the timelines in the multiverse. “Everything” is a vague statement because Ben referred to the universe as everything when it was destroyed, but the Chrono navigation statement has no clarification of that nature. This is a rather vague statement. Servantis, similarly, says that as a Celestial sapient, the omnitrix wielder could “wish everything out of existence.” An author once claimed Alien X could destroy the omniverse in six thoughts, but he claims to not remember saying that. Either way, there are statements in the show that seemingly confirm this.
Naljians state that there are only 26 dimensions that matter, but we can deduct from other statements that there is much more to the omniverse.
An Ultimate Galvan, Albedo, after absorbing Azmuth’s brain, states that “We are all dust bound by one enormous universal force, no not universal, not even multiversal, this omniversal force continues forever, in every direction through every reality.“
What are the other dimensions then? Since there are, according to this statement, infinite dimensions, the Ben 10 omniverse is not likely bound by string theory. It is possible that the first 26 are derived from bosonic string theory and quantum physics, while the others are unknown in nature, seen as they “do not matter” to the naljians. They could be conceptual dimensions, or dimensions outside of defined space. This, however, is a mystery.
It is possible that Alien X is even stronger that being able to destroy infinite planes of existence because claimed he lives outside of space, but that is difficult to gauge in itself. Azimuth’s statement could hunt at infinite dimensions, or it could mean expanding in all 3 dimensional directions, but due to string theory i’m inclined to say he’s referring to higher planes of existence. Cross-dimensional cosmology does not equate well, so it is difficult to scale Alien X to other extra-dimensional beings as a result. However, at least within his realm, he is a being of a higher existence, imperceivable to us.
So how powerful is Alien X?
The true extent of his power is mysterious.
But how powerful do I believe Alien X is?
Unfathomably.