During a walk Ben finds the Omnitrix, which latches onto his arm. Unable to remove it, he uses its powers to become a superhero, fighting evil both extraterrestrial and criminal. However, he finds the job trickier than he imagined, especially with the evil alien warlord Vilgax pursuing him relentlessly to retrieve the Omnitrix. No matter what bizarre form Ben takes, inside he is still the same mischievous 10-year-old boy. He is something of a glory hog, sometimes taking credit that he does not deserve. He also tends to be a sore loser, especially when it is Gwen - with whom he shares a love-hate relationship - who outdoes him. Ben is not above using the Omnitrix to pull pranks, even during urgent situations. In spite of all this, Ben is good-hearted and will stop at nothing to protect his family or anyone in danger. Even when not in alien form, Ben's resourcefulness has saved himself and others from many a dire situation, especially when the Omnitrix cannot activate or does not provide him with the form he originally wants. His most frequent catchphrase, usually said when something goes wrong, is "Aw, man!" His others include "It's hero time!" and "Going hero!".
Ben's relationship with Gwen in the original series is complex. The two of them bicker almost constantly, can hardly agree with each other on anything (the only exception being their dislike of Max's bizarre cooking), and their fights have, on occasion, even led to physical confrontations. Despite all of this, they truly care about each other, showing genuine concern when the other is in serious danger. A prominent example is in Ben 10: Secret of the Omnitrix, when Ben is deeply saddened when it is thought that Gwen had died, and hugged her while in tears when it is revealed that she had survived.
In "Goodbye and Good Riddance", it is shown that Ben is -or was- very unpopular at school, being picked on by the other kids on a regular basis, although this changes after the entire population of Bellwood learns of his Omnitrix-fueled exploits over the summer. Also, in "Last Laugh", it is revealed that Ben had suffered from coulrophobia for some time, but gets over it in order to fight Zombozo.
Twenty years into the future, Ben (voiced by Fred Tatasciore) has become a full-time superhero. He no longer bothers to conceal his identity, as he is recognized everywhere as Ben 10,000 or Ben 10-K, no matter what alien form he is using. He also has 10,000 alien forms, hence the name, and has once again unlocked the Omnitrix's master control function, allowing him to switch forms at will. Having been fighting crime for such a long time, Ben 10,000 has grown into a more strict and serious character, going so far as to stop naming his aliens (which the present Ben considers "half the fun" of using them), and has a darker way of dealing with villains, such as defeating Vilgax by literally dismembering him, though his interaction with his past self in the episode "Ben 10,000" causes him to lighten up somewhat, naming his aliens all over again. Ben's alien forms have aged with him, which is evident in their appearances and abilities. For example, Ben 10,000's XLR8 is noticeably taller with grey outlines in place of the ordinary blue, as well as being considerably faster. In an alternate timeline, Ben eventually has a son named Ken, whom he teaches to used the Omnitrix in the episode "Ken 10".
In the sequel, Ben 10: Alien Force, Ben (voiced by Yuri Lowenthal) is a much more mature and resourceful character, having learned the value of teamwork through his role as a goalkeeper for his soccer team, at the same time growing out of his childish antics, and is far more thoughtful when using the Omnitrix, actually thinking about which alien would be most effective against an opponent or the most appropriate for a situation, rather than simply picking the one with the most physical power as he originally did, though there is still a bit of the young Ben Tennyson in him. His relationship with Gwen is also better; they no longer fight, and their quips about one another are more friendly. He now sports a black shirt, a green jacket with a white vertical line and the number 10, while his soccer uniform resembles his original clothing. He found a way to remove the Omnitrix roughly five years before the series began, allowing him to live a normal life. When Grandpa Max goes missing, he teams up with Gwen and a reformed Kevin to find him. The Omnitrix has been recalibrated, giving access to a new set of alien forms; in addition, it reconfigures into a more watch-like shape. It also carries a new weakness: if Ben's aliens are hurt, when the Omnitrix times out, so too is Ben hurt as a result, though this has not proven to be any real problem so far. Contrary to the Omnitrix's previous ill-timed deactivations, the new recalibrated Omnitrix appears to deactivate more or less to Ben's will, and can be used multiple times in succession or indefinitely when used at its maximum, though its power will eventually deplete and will require time to recharge. Although he, like Gwen, is a descendant from the Anodite race, Ben does not bear the "spark" to use their powers. Ben has learned some degree of martial arts taught by his cousin Gwen..
Gwen shares a love-hate relationship with Ben, insulting him with dry wit and sarcasm most of the time.. She uses her laptop to research any strange people and/or creatures they might come across, and is a capable gymnast and has had some training in martial arts. She has also shown an almost innate skill in using various complicated devices or objects, such as in the "What If?" episode "Gwen 10", when Gwen gained the Omnitrix instead of Ben and proved to be far more adept in its use than he initially was.
Overall, her most notable skill is her innate, if latent, ability at magic. Having within her what Charmcaster calls a "magical aura", Gwen is capable of using various magical artifacts and spells. When using the magical, luck-giving Charm of Bezel, she was able to activate it instinctively, whereas Hex did or could not. Later on, when she takes and uses his staff, she was able to make it fire an energy blast—according to Charmcaster, only someone of Hex's skill should have that ability. Gwen starts tapping into her magical powers when she procures a book of spells from Charmcaster in the episode "A Change of Face".
In the possible future of "Ben 10,000", Gwen (voiced by Tara Strong) has gone by her full first name since college. A combination of physical and magical training leads her to become both a black belt and a master magician using the Charms of Bezel (Gwen has traveled to the Dimension of Bezel where a new set of charms was created for her), which makes her a hero in her own right. In "Ken 10", Ben's son, Ken, looks at her as more of an aunt than a cousin. She does not appear in person during the episode, being on a mission on another planet, but she makes two appearances as an astral projection; first appearing during Ken's birthday party to give him his present (a self-regenerating, dog-like member of the stone creatures that Charmcaster commonly uses as watchdogs and familiars), and then talking privately with Ben about Ken's behavior with his Omnitrix after Devlin's attack on their home.
On two occasions, Gwen has the Charms of Bezel to become a superheroine by the name of Lucky Girl. At first, her ability drew from the "luck" Charm of Bezel, which innately gave her perfect luck. While wearing the charm, any action she took would result in an Rube Goldberg-style chain reaction benefitting her original intent, but usually injuring Ben in the process. She later brought back her superhero identity after obtaining the Keystone of Bezel, which increased her natural abilities to superhuman levels rather than just affecting her luck. Both times, Gwen was forced to retire when the Charms of Bezel were destroyed.
In the sequel, Ben 10: Alien Force, Gwen (voiced by Ashley Johnson) is now a black belt. In this version, Gwen wears a plain, blue shirt with a white collar, a black skirt with black tights, her hair is much longer and darker, her eyes are much darker, and her lips are more visible. Her magical abilities have also grown considerably. She is able to create energy constructs for nearly any purpose, usually creating platforms to levitate herself (and others), beams to grab enemies, and circular blasts to knock enemies back. She also has a wide range of other loosely defined magical abilities, such as dowsing and clairvoyance. Her powers are revealed to be alien in origin; her grandmother, Verdona, is an energy being known as an Anodite. Verdona tells Gwen that what she and others originally thought of as "magic" was actually the manipulation of a Force-like energy called mana. Verdona offers to take Gwen to her home planet and train her in the mystical ways of the Anodites, but Gwen prefers to remain on Earth with Ben and Kevin. She hates being called an "Energy being", referring to her Anodite heritage.
Max was once in the Army, had joined the astronaut program, and was a "plumber" (among other things, it seems) and has been through his share of scrapes; he takes his grandson gaining superpowers in stride and supports Ben in any way he can. Ben and Gwen were ignorant of this at first, believing him to have been a literal plumber. They began questioning this after several incidents in which he displayed knowledge and skills that a plumber would not normally have; everything from military-style hand signals to a working knowledge of nuclear reactors. Throughout the first season, it seems that Max knows far more about aliens than he lets on, which climaxes in the season finale, where it is revealed that he and Vilgax are old enemies, with Vilgax even going so far as to call Max "a thorn in his side."
In reality, Max was indeed a plumber, but not the kind that Ben and Gwen thought he was. He was part of a government organization called "The Plumbers" which dealt with extraterrestrial, paranormal, and other situations that many others could not handle. Their base was beneath Mount Rushmore. The group was disbanded shortly after Max defeated Vilgax for the first time, suggesting that Vilgax had been largely responsible for the various incidents they dealt with. Max was to have been among the candidates eligible for the Apollo 11 mission, and would have gone were it not for other concerns.
By the age of 80, Max has further modified his RV, grown a beard, and lost his right arm in the Limax Wars of 2017. In its place, he uses a neuroprosthetic replica of his arm, which can also extend and transform into a selection of futuristic weapons. Further in the future (now 92), around when his great-grandson Ken is 10, Max has lost his beard and much of his weight and height, which was explained as being due to his age and a steady diet of futuristic health food; in this future, his cybernetic arm appears far more mechanical, as opposed to before, when it appeared to be an exact replica of his original arm.
Max is an old friend of an alien named Xylene. She had intended to send the Omnitrix to Max, but Ben found it by accident. Max and Xylene seem to have been romantically involved and work well as a team. Xylene tries to convince Max to form a partnership and travel across the galaxy with her, but Max eventually turns her down twice: the first time due to his duties as a Plumber, and the second time due to his need to look after the kids.
In Ben 10: Alien Force, Max looks mostly the same as before, save for a couple of minor wrinkles and whiter hair. He disappears shortly before the start of the series, leaving only a holodisc with a message for Ben. In the message, he states that he is investigating renewed alien activity on Earth and that Ben need not worry. A follow-up message erroneously claims that he has the Omnitrix, followed by an image of a DNAlien flickering at the end, possibly meaning that the message (the part about the Omnitrix, at least) was recorded by a DNAlien, perhaps the one that Ben confronted in the Rustbucket. In "Kevin's Big Score", Kevin tracks down a second holodisc containing a message from Grandpa Max. This one, while still cryptic, does not contain any hints of deception as the first does. In it, Max advises Ben to form a team to fight the alien threat, recommending that he track down other child Plumbers. He appears in person in "Max Out", where he infiltrates a Highbreed factory to rescue Ken Tennyson (Gwen’s brother, not Ben's future son), and is captured by him, partially mutated into a DNAlien. He is reunited with Ben and Gwen when they come to free him. In order to stop the factory from mass-producing DNAliens, Max uses a Null Void Projector (minus the focusing lens) as a hand grenade to destroy everything within a half-mile radius, seemingly killing himself in the process.
After arriving on Earth to arrest Sixsix and Vulkanus, Ultimos grants Ben an honorary membership in their organization, the Omnitrix making him a hero by proxy. Tini develops a crush on Ben after first seeing him, Ben having inadvertently timed his transformation into Fourarms with their arrival. He makes it a point to avoid the form afterwards, despite Tini's desire for him to use it. This in turn brewed up jealously in Synaptak, who is in love with Tini. Ben, however, is perceptive enough to catch onto this and goads Synaptak into revealing his feelings for Tini, granting both their wishes.
The three appear again in "Ben 10,000", where future Ben's near-perfect policing of the entire planet leaves them basically without a job, being forced to ferry Ben's captured criminals to prison instead. After future Ben is "reformed" by his past self, he tells them to handle the Neuvo Circus Freaks in his stead. They have not appeared in the "present day" of the series since their first appearance.
Although only three members have been shown in the actual series, it has been hinted that the Galactic Enforcers have had many other members who have served in the past. In fact, the very first group of Galactic Enforcers were responsible for creating the prison colony Incarcecon, which Ben visited in Secret of the Omnitrix.
Unlike the other hunters, Tetrax is allied against Vilgax. Upon first discovering that Ben has the Omnitrix, he laments the fact that out of the planet's six billion inhabitants, it would end up on the wrist of a child. He also berates Ben's lack of strategy in regards to its use. After helping Ben to defeat the other hunters, during which Ben learns to use the Omnitrix strategically, he decides that the Omnitrix is in good hands, allowing it to remain with Ben. He also gives Ben his hoverboard, which contained a message that revealed his real name, saying that it might come in handy. Ben uses it several times throughout the series (using it for the first time, at least on-screen, in "Tough Luck"). In Ben 10: Secret of the Omnitrix, the hoverboard is melted in a vat of acid, but Ben is given a replacement.
Tetrax returns in Ben 10: Secret of the Omnitrix, where his past is explained. As a being who cared about no one but himself, he became a mercenary and ended up hiring himself out to Vilgax. When he finished the job Vilgax gave him, Vilgax created a weapon and used it to destroy the Petrosapien homeworld when they would not bow down to him. This caused Tetrax to betray his former employer, and he now works to rid the galaxy of his evil and prevent other superweapons (such as the Omnitrix) out of Vilgax's hands. He arrives on Earth after receiving the Omnitrix's SDM (Self Destruct Mode) signal, and takes Ben aboard his ship in search of Azmuth, the creator of the Omnitrix and the only one who can deactivate the self-destruct function. Unfortunately, Tetrax's problems are multiplied when Gwen stows away aboard his ship, and Ben's transformations are revealed to accelerate the countdown.
On the planet Incarceron, Tetrax runs into Sixsix, another of the bounty hunters hired by Vilgax who ended up on the prison planet. After a brief battle, he and the Tennysons find Myaxx, Azmuth's former assistant. Because of her, Tetrax is forced to reveal that the Omnitrix's explosion will create a shock wave affecting the entire universe, instead of just the wearer as he told Ben. Myaxx then leads the group to Azmuth's compound on Xenon, where he faces Sixsix again twice before defeating him. After Vilgax is also defeated, Tetrax returns Ben and Gwen to Earth and departs.
In the live action movie Ben 10: Race Against Time, he is seen as a new-age style parent who wants Ben to have his "freedom," insisting on being called Carl, not dad, and letting Ben run off on mysterious adventures without asking questions. He seems to be even more laid back than his wife, and is seen at least twice telling her to let Ben have his fun. For instance, near the end when Ben's mother tells him to not eat too much cheese, Carl says to "Let the kid live a little, and eat all the cheese he wants." Like his brother, Carl is also a descendant of the energy-based Anodite race, but he does not bear the "spark" to use their powers.
JT and Cash also appear in Ben 10: Race Against Time, where they, as usual, take pleasure in picking on Ben. JT is played by Tyler Foden, while Cash is played by Tyler Patrick Jones. In Ben 10: Alien Force, they are members of a rival soccer team. JT and Cash also appear in "The Gauntlet" where Cash is possessed by an evil robot within the Gauntlet they steal from Kevin's car. It is revealed in that same episode that Ben and JT were friends in the first grade.
Julie later plays a bigger role in "Pier Pressure", where Ben manages to ask her out on a date (with help from Gwen). Their romantic evening at the pier soon turns wild when a dog-like Galvanic Mechomorph attacks the area. Although Ben is initially desperate to hide his heroic lifestyle from Julie, he is eventually forced to come clean about it. Julie is quite accepting of Ben's Omnitrix-fueled exploits, and later helps him to repair a damaged Mechomorph ship.
In the first season, Vilgax is confined to a regeneration tank after being severely injured by the final attack from Xylene's ship, ordering his robotic minions and cosmic bounty hunters to track down the Omnitrix for him. While his body is repaired, he is cybernetically enhanced, making him more than a match for any of the Omnitrix aliens after finally emerging from the tank. Furthermore, the modifications greatly augment his physical prowess, allowing him to easily to leap above skyscrapers, survive in space for a short amount of time, and smash apart mountains with his bare hands, along with being able to increase his strength at will. Even before his modifications, Vilgax had uncanny resistance to harm, being able to survive a nuclear explosion at point blank range. During the Tennysons' run-in with Rojo, Vilgax establishes a psychic link with Ben (something he seems unaware of) which is how the Tennyson's knew in advance about Vilgax's arrival. At the end of the first season, Vilgax tries to retrieve the Omnitrix himself, but is fought off by the Tennysons. Vilgax's ship, the Chimerian Hammer, is destroyed with him still aboard.
In "Truth", Max tells Ben and Gwen how he had a run in with Vilgax who was stealing warheads from a military base when Max and his partner showed up. In the resulting fight, Vilgax was strapped to a warhead by Max and launched into his own ship. At that time, Vilgax was only slightly larger than a human man, compared to his now colossal size (perhaps an addition to his cybernetic augmentation).
At the end of the second season, Vilgax is still alive, having survived the destruction of his ship by teleporting out just before the explosion. He is found encased in ice by Kevin 11, and gets into a brief skirmish with the latter when Kevin claims that he "doesn't look so tough". Discovering Kevin's connection to the Omnitrix, Vilgax decides to team up with him in another attempt to retrieve the Omnitrix, but both are locked away in the Null Void dimension by the end of the episode.
In the episode "Ben 10,000", set twenty years in the future, Vilgax eventually escaped the Null Void by stumbling across a Null Void portal being opened on another planet, but lost yet another battle to Ben 10,000. This time around, Ben didn't take any chances with Vilgax's defeat, literally tearing him apart. Dr. Animo resurrects Vilgax using his Transmodulator, giving him a stronger new form with enhancements such as genetically implanted weapons (such as ropes and mines in his right arm) and bio-boosters, and knowledge of all the future Ben's alien moves, and the two of them then attempt to get revenge, only to be defeated by both the present and future Bens and Gwens. Ben 10,000 defeats Vilgax by freezing him in a river.
A dream version of Vilgax appears in the episode "Perfect Day", where he appears to confront Ben. The battle lasts for a short time, and then Vilgax tries to send Ben to the Null Void. As Fourarms, Ben throws him in instead, but this proves to be an error on the part of the Forever Knights, as Vilgax was about to send Ben to the Null Void without first obtaining the Omnitrix.
Vilgax appears in Ben 10: Secret of the Omnitrix, where he once again attempts to retrieve the Omnitrix. During a flashback, Tetrax reveals that Vilgax destroyed the Petrosapien homeworld, and he (Tetrax) unwittingly gave Vilgax the final element needed to carry out his plan. Vilgax has somehow found a portal out of the Null Void, and he refers to his anger at having been trapped there (including showing a short nervous twitch at its mention), which has deepened his grudge against Ben to the point where he refuses to acknowledge the danger threatening the universe if the Omnitrix self-destructs (but nevertheless gains enough respect for Ben to the point of calling him by his first name instead of his last name). He encounters Ben aboard Tetrax's ship and attacks him, only to be shot out of the airlock by Ben. He is eventually defeated when Azmuth, the creator of the Omnitrix, gives Ben access to a massive alien, Way Big, who hurls Vilgax into outer space.
Vilgax returns in "Goodbye and Good Riddance", yet again to steal the Omnitrix. Through the combined efforts of Ben and his father, Vilgax is caught in a natural gas explosion. It is unknown whether or not he survived, although he had to be resurrected by Animo in the episode "Ben 10,000", stating he was killed by this. However, as Ben 10,000 never explicitly stated when he "left him in pieces" it is possible that he survived and may return in Ben 10: Alien Force to get revenge on the Tennysons and attempt to steal the Omnitrix once again.
In the final scene of Ben 10: Race Against Time, an alien ship resembling Vilgax's is seen flying towards the Earth right before the credits roll, but whether or not this is indeed Vilgax is unknown.
Vilgax is shown as his future form in Ben 10: Protector of Earth. After being released from the Null Void by Ghostfreak, Vilgax sends a small mosquito-like drone to go to the Omnitrix and extract the DNA from it. Using the DNA, Vilgax plans to use the Null Void, plus other Plumber technology, to create a vortex large enough to erase Earth from existence. To stall for time, Vilgax sends Dr. Animo, Ghostfreak, and Floraunas to distract Ben, giving him more than enough time to prepare. However, due to Ben shooting Vilgax through space via an airlock, Vilgax is warped back to the Null Void, along with his ship, and presumably the Null Void Projector. After the credits, Vilgax is shown to have survived, minus his limbs and being repaired by robots, vowing to come back.
The original purpose of the Forever Knights is the slaying of a dragon (actually an alien) that had been captured 1000 years prior. This led to the acquisition of both human and alien technology in hopes of finding a weapon with which to kill it, meaning everything they did in the original series was for the sole purpose of acquiring weapons they could use to slay the dragon.(i.e. the Sword of Ekchuah, the Sub-Energy, the Omnitrix, etc.). This is apparently a dedication handed down throughout the ages, as the prospect of finding more dragon-like aliens serves to motivate the group once again after the first one escapes.
The Forever Knights first appear in the episode "A Small Problem", then known only as The Organization (according to the enhanced version of "The Ultimate Weapon", this is one of their codenames they use to prevent linking them to their crimes). They attempt to dissect Grey Matter, but are thwarted. Their base is also destroyed, along with the advanced technology stored on the site. They returned again in "Ultimate Weapon", in which their formal name is used.
In "Perfect Day" they returned, attempting to steal the Omnitrix while trapping Ben in a dream world, using some sort of dream-inducing device. While Ben was in the dream world, the other Forever Knights members were using their technology to remove the Omnitrix. However, they fail when Ben takes control of the dream and wakes up.
The rest of the Forever Knights return in "Ben 10 vs. The Negative 10" to help their leader obtain the Sub-Energy, the world's strongest energy source, but are defeated along with the Negative 10 by the end of the episode.
The Forever Knights appear in Ben 10: Protector of Earth, but are shown not to be villains when you complete the South West, later in the game. They manage to discover Vilgax's plan and attempt to use the Cannonbolt DNA extracted from the Omnitrix, combined with a giant robot, to take down Vilgax before it's too late. However, Ben, mistaking Enoch for the main villain, destroys his weapon and makes him unable to stop Vilgax.
The Forever Knights reappear in Ben 10: Alien Force. Here, they are allied with the Highbreed and the DNAliens, although they are unaware (or perhaps uncaring) of their true intentions. The Forever Knights now dress in full plate armor with an infinity symbol on the abdomen, as opposed to the more medieval-style armor they wore previously.
Kevin Ethan Levin (voiced by Michael Reisz in his first appearance, Charlie Schlatter in his following ones, and by Greg Cipes in Ben 10: Alien Force) is a mutant with the ability to absorb any type of energy and release it at will. The energy can be used to activate or overload various machines and can also be used to make energy blasts. When absorbing energy from the Omnitrix's aliens, he becomes an incomplete, but effective, version of that alien. In his first appearance in "Kevin 11", he is first encountered by Ben in an arcade, where he was assaulted by bullies and saved by Ben and XLR8. The two attempt to steal video games from a warehouse and get caught by the police, forcing Ben to reveal his powers to him in order to escape. Eventually, Ben breaks off their partnership when Kevin rigs two trains to collide, not caring that hundreds of innocent people would be killed. He then absorbed the abilities of Heatblast and Fourarms, using the former form's powers to get revenge on those who had wronged him. He absorbed the latter form's powers during his second battle with Ben to even the odds. After trying to take the Omnitrix from Ben, the Omnitrix emitted a feedback pulse to prevent Kevin from taking it, seemingly neutralizing his power. Kevin, however, exhibits the ability to create flame at the end of the episode.
Kevin serves as the main antagonist of the second season. His ability to project heat at the end of "Kevin 11" is a result of the Omnitrix's feedback pulse: the amount of energy it emitted allowed him to fully absorb its powers, giving him access to every alien form Ben had at the time. However, because Kevin's ability to regulate this power is poorer than that of the Omnitrix itself, the energy suppresses his human form and forces him to remain as an alien most of the time. As revealed in "Framed", Kevin blamed Ben for this, so he used the powers of the Omnitrix to start a crime spree in Los Angeles, both for his own benefit and to damage Ben's (or rather, his alien forms') reputation. Eventually, Kevin's ability to regulate the power fails altogether, causing him to permanently mutate into what Vilgax would describe as a "misshapen, chaotic amalgam of creatures from the Omnitrix."
After his mutation, Kevin gloats that he has all of Ben's powers plus his own, making him "Kevin 11" (the name Kevin is credited under in the ending sequence of the show). Despite Kevin's claim, Ben notes that Kevin's powers are only one-tenth as strong, (although this assessment may not be accurate) and Kevin never exhibits his original powers in this form (the same is true for Ghostfreak, Upgrade (though this is debatable when Kevin used XLR8's tail to slam a tray of Megacruiser food into Technorg's face), Grey Matter, or Wildmutt. Kevin's form also limits his ability to use the special powers of his alien forms. Being a random fusion of aliens, Kevin only has access to the powers most prevalent in his form. In addition to these limitations, Kevin seems unable to use the powers of any aliens Ben has gained since their original encounter.
During his third appearance in "Grudge Match", Kevin attacks Ben to get revenge, blaming his condition on Ben. As the two battle, they are abducted and forced to fight in Slix Vigma's gladiator games. During their battles, Ben helps Kevin to realize the advantages of his mutated form. Because Kevin 11 is an amalgam of aliens, he can mix and match their powers to make up for their reduced potency. Although forced to work together, Kevin's only goal was killing Ben. He is transported to a different galaxy at the end of the episode while locked in combat with Technorg, whom he managed to kill. He then took the ship as his own.
Kevin returns in the episode "Back With a Vengeance", where he teams up with Vilgax to defeat Ben, and eventually manages to remove the Omnitrix. However, he betrays Vilgax later in an attempt to leave both in the Null Void and use the Omnitrix to take over the world, only for Ben to escape and leave him and Vilgax trapped instead.
In "Ken 10", Kevin returns after at least thirty years of imprisonment in the Null Void (though he has been sent in and out several times prior to the episode), having been set free by his son, Devlin Levin. Devlin was born after one of these escapes in which Kevin fled to a colony on Saturn, where he started a family before being captured again. Kevin has now fully mastered his powers and can return to his human form. In his human form, he can also utilize the powers he has absorbed to a limited extent, such as XLR8's speed, without having to transform into that alien, and is able to simply shrug off an intense beating from Way Big. His mutated form, though still an amalgam, has changed considerably from his continued absorption of alien DNA, leading to his new title of "Kevin 11,000". Eager for revenge and having not so much as a care for his son, despite Devlin's role in releasing him, Kevin proceeds to beat on Ben and his son, Ken. Ironically, it is Devlin who stops him, trapping his father back in the Null Void.
In the video game Ben 10: Protector of Earth, Kevin as a mini-boss Ben fights at the end of Lumber Mill. He reappears when a Null Void portal is opened up and frees him. While Ben deals with several monsters also unleashed as a result, Kevin kidnaps Max and takes him to the Lumber Mill. Once beaten, Kevin is sucked back into the Null Void.
Kevin reappears in Ben 10: Alien Force as an ally of Ben and Gwen. Kevin's powers operate differently from the way they did in the original series. He has a normal human form, and his absorbing abilities now allow him to absorb the properties of matter as opposed to draining energy, allowing Kevin to cover himself and others with a layer of any solid substance he is touching (similar to Marvel's Absorbing Man). He has a green sports car which he takes care of obsessively. Through the years, Kevin has gained a considerable amount of knowledge about aliens, possibly through his brokering of alien technology to various aliens and the Forever Knights, this and possibly because he spent a short amount of time in space. He also seems to know a lot about humans with an alien heritage, hinting that his powers may have come from alien ancestry, and that his guess about Gwen's powers being of alien origin was proven correct. As revealed in the episode "The Gauntlet", Kevin, as mentioned by JT, is now reputed as "the toughest kid in town", indicating that he has taken up residence in Ben's hometown.
In "Darkstar Rising" he reveals that his father was also a Plumber. He never met his father, but his mother told Kevin about what his father did. This could be were he gets his powers, seeing as many of the other half aliens they had met alien parents's were Plumbers. At the end of the same episode, Kevin, along with Gwen and Ben become official Plumbers.
Zs'Skayr is the main antagonist in the third season, returning in the two-part episode "The Return"/"Be Afraid of the Dark", where he is resurrected by an alien scientist named Dr. Vicktor. Gathering a group of horror-themed aliens as minions, Vicktor enacted a plan to resurrect Zs'Skayr, whose master plan was to plunge the Earth into darkness, just like his actual home world. Zs'Skayr himself is still intent on gaining control of the Omnitrix. Using corrodium retrieved by the mummy alien in "Under Wraps", they set up a corrodium beam that will block out light from the sun, allowing Zs'Skayr to exist in eternal darkness. Zs'Skayr succeeds in doing so, allowing him to reach his full potential, but only for a while before Doctor Vicktor accidentally rammed Max into the corrodium projector during a dogfight. In the end, Ben kills him once again on board a space shuttle, when Max opens the shuttle's roof and exposes him directly to the sun. Ben regains use of the form during this time, except in Ghostfreak's natural state, indicating a possible return.
Zs'Skayr appears in Ben 10: Protector of Earth as the main boss of the North East, and is fought in Gold Coast Theater or Effigy Mounds in Hex's body. While not the main villain, he is the one who frees Vilgax from the Null Void and instigates the plot. He appears similar to his form in "Be Afraid of the Dark", having shoulder spikes and more detailed features.
During the Ben 10 Week event on April 13, 2008, revealed his real name and that he was High Ecto-Lord of Anur Phaetos. He learned about the Omnitrix when one of Vilgax's data probes crash landed and he read its data files. Not long after, he met up with Myaxx when she was scouting the planet for DNA samples and aided her in acquiring samples from the nearby planet of Flors Verdance. However, Zs'Skayr possessed the Florauna Myaxx was sampling and used his powers to allow his DNA to enter the Omnitrix along with the sample.
The Loboan appears as an enemy in Ben 10: Protector of Earth in two variants: Fangface and Fangface Howler.
The Negative 10 consists of:
The Negative 10 (sans Driscoll and the ninja) are defeated when the Tennysons exploit their competitive feelings towards each other and trap them in the force field which previously stored the Sub-Energy.
By using the Transmodulator, a device of his own design, Animo can mutate animals into giant versions of themselves. The second phase of his work involves reanimating dead cells, allowing him to literally resurrect the dead (though, as seen with the T-rex he reanimated in that same episode, it is possible that his reanimated creatures are not truly alive, but merely undead). All of this is in pursuit of the award which he had lost. His quest ends in failure, since Ben was there to stop him, reversing the effects of his Transmodulator by damaging it. He is arrested in that episode, and Ben takes his original Transmodulator as a trophy.
He appears again in the episode "Dr. Animo and the Mutant Ray", where he creates a much larger version of the Transmodulator using the broken-off faceplate of the Omnitrix. This version mutates living creatures with alien DNA, creating odd mixtures of alien and terrestrial creatures, such as a "Heatbat". Before he can complete his plans to use a satellite to shoot the ray all over the world, Ben stops him with Gwen's help. Since his mutants were never shown being cured, it is possible that they are still around. From then on, he attempts to steal DNA from the Omnitrix. For some reason, his trademark giant frog is also present, though he may have simply re-mutated it sometime after his original defeat. How and when he escaped is unknown.
In "Ben 10,000", Animo is still alive in the future, though his head is the only part of him that remains. He had attempted to gain Kevin 11's powers by recreating his mutation. He failed and destroyed his body, but managed to survive by placing his head in a special preservation tank. However, it controls a unique apparatus that allows him to attach himself onto animals specially reformatted with a similar device (in this case, an albino gorilla, Making him look very similar to DC comics villain Ultra-Humanite) and control them. He was the one responsible for creating Exo-Skull and resurrecting Vilgax, as well as organizing the "Interspecies Gang", a band of human/animal hybrids created by Animo which serves as a key antagonist in Ben's future. He is defeated by both Gwen and her future self, Gwendolyn, as well as a cybernetically-enhanced Max.
In "Divided we Stand", the present-day Dr. Animo escapes from prison with the help of a mutated seagull, and is soon resuming his experiments. After capturing one of Ben's Ditto clones (the alien only recently discovered by Ben), Animo creates an army of self-multiplying mutant Stinkflies, but Ben exploits the inherent weakness in the clones to destroy every Stinkfly clone and capture Dr. Animo once more. Afterwards, Max deletes all of his computer files, preventing him from copying any more Omnitrix DNA if he escapes again.
He also appears in Ben 10: Secret of the Omnitrix, but only as the instigator of the main plot. In it he tries to create a DNA bomb that was designed to devolve all life on Earth. He is defeated and the bomb is disabled, but a stray burst of energy is still emitted by it. Ben's Omnitrix absorbs the energy, causing it to start a self-destruct sequence and therefore beginning the plot. The Enhanced version of the movie mentions that Animo has learned how to control animals psychically, a talent learned from Clancy during his time in the Negative 10. Dr Animo was also mentioned in "Ken 10", as his actions caused Ben to move the Null Void chamber for safe-keeping.
He appears in the episode "Ben 10 vs. The Negative 10" as part of the Negative 10. He was then joined by a mutant bat and prairie dog. He makes a brief appearance at the end of the following episode, "Goodbye and Good Riddance", wearing an exo-suit resembling a headless Trojan Horse, and leading a group of animal mutants towards Ben's school, and Ben and Gwen prepare to fight him as the original series comes to an end.
Dr. Animo appears in Ben 10: Protector of Earth as the main villain of the South East, and is fought at Oil Refinery. His Omnitrix-created mutants serve as Ben's foes through those stages and he battles in a robotic gorilla suit, similar to his appearance in" Ben 10,000", although the in-game version is obviously more robotic and is merely Animo in a suit, instead of being a disembodied head on a cyborg gorilla.
In her debut appearance, "Tough Luck", she busts her uncle out of prison and assists him in trying to steal the Keystone of Bezel. She manages to trick Gwen by putting on an act about hating her uncle, only to swipe the Keystone while hugging Gwen. She then gives Hex the Keystone. In the end it's revealed that Hex needs the Keystone to recreate the Charms of Bezel, and that she is manipulating her uncle into doing it so that she can take their power for herself. In the end, her powers, like Hex's, seem to be absorbed by the Keystone.
Charmcaster returns in "A Change of Face", her powers having regenerated since her recent encounter with the Tennysons. She attempts a body swap spell with Ben, hoping to take advantage of the Omnitrix in order to boost her magic. Her efforts fail, however, as her three attempts end in swapping with Gwen, being returned to her normal body while Ben and Gwen are swapped, and returning Ben and Gwen to their normal bodies respectively. She is arrested at the end of the episode, and her bag is tossed into the sea. She is last seen in a juvenile detention ward, where she is about to be beaten up by two female inmates whom Gwen spurned while she was in Charmcaster's body. Gwen procures her spellbook during this period, and keeps the item as a souvenir, eventually learning to use it.
Charmcaster makes a small cameo at the end of "Don't Drink the Water", where she is seen taunting her uncle (who has been reduced to an infant by the Fountain of Youth) and saying that she's giving the orders now.
She appears in "Ben 10 vs. The Negative 10" as part of the Negative 10. Although loyal to Driscoll and his plans, she is more concerned with crushing her arch-rival Gwen than anything else. She also is shown to have a slight rivalry with fellow teammate Rojo.
Clancy originally lived at 8610 Chester Street, an abandoned apartment building. When Councilwoman Liang tries to redevelop the area and have his home torn down, he kidnaps her with the intention of feeding her to his insects. Fourarms stops him, but accidentally destroys his home in the process when Clancy's insects swarm him. After that plan fails, Clancy tries to cause the nearby nuclear power plant to meltdown, killing everyone and everything in the city. Clancy makes himself a protective suit out of cockroaches (which are presumed to be the only living creatures on the planet that would survive a nuclear war) in order to survive the blast. A sick Heatblast, whose powers are reversed by the virus, giving him the ability to control ice instead of heat, stops this plan by freezing the reactor core. Finally, he attempts to take revenge on the trio. Once again, he is stopped, this time by Max's San Ju Yen Pien cold medicine, which attracts the bugs and overrides Clancy's control over them, at which point Max knocks him out with a single punch and leaves to call the police.
Clancy doesn't appear to actually be deranged at first, just someone who was trying to save his home (though his comment about letting his bugs eat the councilwoman seems to be going a bit overboard), but he starts doing things that show him to be psychotic when the building is destroyed along with most of his bugs.
In "Ben 10 vs. The Negative 10," he joins the Negative 10 and has since been mutated into a monstrous, dragonfly-like creature; due to this form's resemblance to Stinkfly, it is possible that Dr. Animo assisted him in using this form. In this form, he no longer demonstrates the capability of human speech and is able to fire swarms of insects from his mouth.
Clancy makes a minor appearance in his human form in Ben 10: Protector of Earth as a mini-boss working for Dr. Animo.
Joey is greedy, wild and amoral, and not hesitant to attack innocent bystanders just because they annoy her. Neither her real name or her cyborg name is mentioned in the show, except for in "Ben 10 vs. The Negative 10," where her name is pronounced with an English "j," but are listed as such in the credits.
Joey returns in "Ben 10 vs. The Negative 10" as part of the Negative 10, with alien technology and armor presumably supplied by the Forever Knights. In that episode she is also shown to have a rivalry with Charmcaster for being the "baddest girl" in the group.
Sublimino first appears in "Midnight Madness." He resurfaces in "Ben 10 vs. The Negative 10" as the new leader of the circus freaks, when the Forever King recruits him, though he is silent throughout the entire special. He does, however, manage to put the technopathic Cooper into a trance, allowing him to hypnotize the young boy into attacking the Tennysons.
In "Lucky Girl", he attempts to steal an ancient spellbook known as the Archamada Book of Spells, dating back to the 16th century and containing powerful spells that, combined with the Charms, give the wielder unimaginable powers. However, the Charm of Luck falls into Gwen's possession during Hex's fight with Ben, and she soon learns to utilize its power (the first hinting of Gwen's latent powers). Despite Hex's attempts to reclaim the Charm and the Book, he is eventually defeated by the Tennysons and arrested, while Gwen destroys the Charms.
Hex returns in "Tough Luck", having been broken out of prison by his niece and apprentice Charmcaster. Together, they search for the Keystone of Bezel, which he plans to use to recreate the other five Charms and multiply his power tenfold. Again, Gwen gets ahold of the Keystone and is soon attacked by the pair. Hex fails again due to both the Tennysons' interference and Charmcaster betraying him so she can take the Charms for herself (though she fails as well).
He then reappears in "Don't Drink the Water", having aged into an old man since his last appearance. Learning of the Fountain of Youth, he tracks it down and uses it to become immortal. However, Ben, reduced to a toddler by the effects of the Fountain, uses Heatblast to evaporate the Fountain, which overexposes Hex and reduces him to an infant. Hex is last seen in Charmcaster's hands, where his niece enjoys taunting him at his expense.
Hex (who is revealed to have been possessed by Ghostfreak once defeated) appears in Ben 10: Protector of Earth, but only as a mini-boss that Ben faces at the end of Effigy Mounds.
Sixsix appears in the episode "Hunted". Sixsix later appears in "The Galactic Enforcers", teaming up with Vulkanus as part of his plan to combine Element X with bisynthium alloy (an unspecified form of iron ore) to create an explosive capable of wiping out an entire solar system. Sixsix and Vulkanus reappear in "Perfect Day" as villains in Ben's dream.
He appears as Vilgax's henchman in Ben 10: Secret of the Omnitrix after Vilgax found him drifting outside Incarcecon. His helmet is broken, revealing a gray-skinned creature beneath; however, the enhanced commentary for the special reveals that Sixsix is a mutant, and that others of his kind do not look the same. Strangely, he seems to become more feral after this happens: Vilgax attaches a leash to him in order to keep him under control. He seems to have developed a grudge against Tetrax since "Hunted", attacking him relentlessly upon meeting him again. He was finally defeated by Tetrax as he tries to escape after Ben defeats Vilgax and his army.
Ben 10: Alien Force introduces the bounty hunter Sevenseven, a visually similar character of the same race described as being far more dangerous than Sixsix. His armor is similar to that of Sixsix, but a lighter shade of purple, and, like Sixsix, he does not speak a word of English (even when talking to those who do), but other aliens are able to understand him perfectly.
He reappears in Ben's dream world in "Perfect Day" working alongside Sixsix again, and in the future episode "Ken 10", where he was defeated by Ben 10,000 and transported to the Null Void dimension.
Vulkanus makes an appearance in Ben 10: Alien Force, in the episode "Kevin's Big Score". According to Vulkanus, he was betrayed by Kevin during a "counterfeit isotope" scam a few years earlier. Kevin left him holding the merchandise when the Plumbers arrived, and though he managed to escape, the Plumbers destroyed his ship. Unable to leave Earth, he resorted to trading low-level alien technology to get by. When Kevin arrives looking to obtain an important item (a holo-disc from Grandpa Max), Vulkanus decides to get back at him for the betrayal by forcing Kevin to absorb a small piece of Taedenite, the rarest living gem in the galaxy. This causes Kevin's body to mass-produce the gem, thus giving Vulkanus an endless supply. However, he is foiled by Ben, who uses Big Chill to literally freeze off his armor, revealing that Vulkanus is really nothing more than a minuscule alien in a robotic suit. Rather than attempt to arrest him, however, Kevin leaves Vulkanus with the small fortune in crystals he had managed to chip off beforehand, considering it as payment for his past actions.