[edit] Villains [edit] Main villains [edit] Vilgax Vilgax (voiced by Steven Blum) is a Chimera Sui Generis, as well as a vicious, intergalactic conqueror, and he will stop at nothing to obtain the Omnitrix and use it to build an army capable of conquering every planet in the galaxy. Vilgax serves as the main antagonist of the first season, responsible for half of Ben’s enemies before appearing in person in the final episode of season one. He is, without a doubt, Ben’s most powerful enemy. He is one of the most feared aliens in the galaxy, having destroyed five planets and created a black hole. In fact he is so feared, that almost no biological lifeform is willing to work for him, forcing him to use robots for his entire crew, though he is able to find mercenaries willing to work for him. 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.[14] While his body is repaired, he is cybernetically enhanced, making him more than a match for any Omnitrix alien after finally emerging from the tank. Furthermore, the modifications greatly augment his physical prowess, allowing him to easily to leap above skyscraper heights, survive in space for a short amount of time, and smash apart mountains, 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 Tennyson’s 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. Vilgax generally responds to weak, semi-hilarious comments in a rather a          but humorous way (such as when Ben asked “I don’t suppose that means you’re gonna let me go now” and Vilgax responds with “hardly”). In “Truth”, Max tells Ben and Gwen how he had a run in with Vilgax. Vilgax was stealing warheads from a military base when Max and his partner showed up. In the resulting fight, Vilgax was          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. 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 10,000 didn’t take any chances with Vilgax’s defeat, literally tearing Vilgax to pieces. Dr. Animo revives Vilgax using his Transmodulator, giving him a stronger new form with enhancements such as genetically implanted weapons 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. This future isn’t necessarily certain, as Ben 10,000 interferes with his own past at the end of the episode, potentially altering events from there-on. 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 unwittingly gave Vilgax the final element needed to carry out his plan. Vilgax refers to his anger at having spent 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 his real name instead of Tennyson). After a series of battles, he is 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 which caused him to be incinerated. It is unknown whether or not he survived, although he had to be revived by Animo in the episode “Ben 10,000″, stating he was killed by this. However, the fact that Ben 10,000 never mentioned when he “left Vilgax in pieces” suggest that Vilgax may have escaped to cause trouble for him later. 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. [edit] Kevin 11 Kevin 11 in his alien form.Kevin (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 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 commit crimes, 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.”[15] 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,[16] (although this assessment may not be accurate) and Kevin never exhibits his original powers in this form. 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 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 and having been set free by his son, Devlin. 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        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 has lost the abilities of Ben’s Omnitrix aliens. Furthermore, his absorbing abilities now allow him to absorb the properties of matter as opposed to draining energy, allowing Kevin to transmute his body into any solid substance he is touching (much like Marvel’s Absorbing Man). [edit] Zs’Skayr (Ghostfreak) Zs’Skayr (voiced by Steven Blum) was trapped as one of Ben’s forms, Ghostfreak, but escaped from the Omnitrix. His evil personality was trapped within the Omnitrix when his DNA was sampled. He finally manages to force his way out of the Omnitrix in “Ghostfreaked Out”. For some reason, Ghostfreak goes by the name Ben gives him, and does not mention having a real name. After peeling off the protective layer of skin that normally covers him, he tries to take over Ben’s body in order to become whole again. After a failed attempt to possess Ben, he coerces Acid Breath, Thumbskull, and Frightwig to help him by taking over Thumbskull and tossing him about the room in a show of force. However they failed and Ben opened a curtain exposing Ghostfreak to sunlight, thus killing him. After this episode, Ben is unable to transform into Ghostfreak. Ghostfreak is later replaced by Cannonbolt in the opening credits at the start of the third season. 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 revived by an alien scientist named Dr. Vicktor. Vicktor’s species is stated to be from Anur Phaetos, the Ectonurite homeworld, in Ben 10: Protector of Earth, though contradicting sources state that they are from Anur Transyl(same star system, different planet). 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 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. 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. [edit] Zs’Skayr’s (Ghostfreak’s) Minions These three aliens appeared in separate episodes during the third season. It is later revealed that they were working together on a complex scheme of Zs’Skayr’s design. It is explained that back when Ghostfreak was still inside the Omnitrix, Ben used him to sneak into a horror movie, at which point he was overtaken by the alien, who contacted Doctor Vicktor with his plans. Zs’Skayr and his minions are all based on horror monsters (Frankenstein’s monster, a mummy, a werewolf, and a ghost), and all come from the Anur system. Doctor Vicktor (voiced by Michael Dorn) is a Transylian from Anur Transyl (an alien resembling Frankenstein’s monster) who works at NASA, disguised as a human scientist as a means to hijack a space shuttle. He is intelligent, and working for Zs’Skayr; his immediate plan was to resurrect his master, whose ultimate plan was to prevent the sun’s light from reaching the earth using various satellites (therefore meaning that Zs’Skayr would be at full power all of the time). He is not treated with respect after Zs’Skayr is resurrected. After he asks why they need Ben, Zs’Skayr takes control of his body and throws him around. He serves as the unofficial leader of the three horror-themed aliens. The purple lightning that the previous two horror aliens appeared in was generated by a teleportation machine that he uses. His name is derived from the name of Victor Frankenstein from the Mary Shelley novel. His first appearance is in “The Return”, where he succeeds in reviving Zs’Skayr. In the next episode “Be Afraid of the Dark”, Ben fights Doctor Vicktor and Zs’Skayr on Earth. Ben accidentally gains use of Doctor Vicktor’s form when Vicktor finds Ben and grabs him by the wrist, unintentionally adding his DNA to the Omnitrix. Vicktor essentially defeats himself near the end of the episode. In an attempt to teleport Ben to an unspecified location, he and the mummy alien are tossed into the portal he created. Ben 10: Protector of Earth features “Vicktors” as enemies on Zs’Skayr’s planet. Mummy: The Mummy appeared in “Under Wraps”, a Thep Khufan from the planet Anur Khufos, was sent by Doctor Vicktor to find a dangerous element called corrodium that crashed on Earth millions of years ago. Grandpa Max explains that the crystals are a potent but unstable power source, and the radiation emitted by the crystals causes almost instant mutation in humans and other Earth-born creatures. Todd Maplewood, a boy Ben and Gwen met, said it arrived in purple lightning, which is the same way the Alien Werewolf arrived in “Benwolf”. Max states there may be a connection between the werewolf and mummy, which is proven in “The Return”. During Ben’s battle with the creature, its DNA is absorbed by the Omnitrix, giving Ben access to the form. The mummy is frozen solid by Upgrade merging with a liquid oxygen device and buried, along with its corrodium, under a thick bed of concrete. It was released by the werewolf in “The Return”, and assists in Dr. Vicktor’s plan to plunge the earth into eternal darkness. When Ben is fighting Ghostfreak, Doctor Vicktor, and Mummy in “Be Afraid of the Dark”, Doctor Vicktor inadvertently sends both himself and mummy to an unspecified location, most likely the Null Void, through an ill-timed use of his teleportation device. Ben’s version of Mummy is named Benmummy. Mummy appears as an enemy in the game “Ben 10: Protector of Earth” as two enemies: Mummy and Cyclone Mummy. Yenaldooshi: This alien werewolf was sent by Doctor Vicktor to steal communication equipment from a reservation that Ben, Gwen, and Grandpa Max were visiting in “Benwolf”. Ben first fights against the Loboan as Wildvine. When Ben is transformed back to his normal self by the Omnitrix, the Loboan slashes the Omnitrix, causing the device to download his DNA (signified by its face turning yellow) and gradually change Ben into the form. In their second battle, the Loboan appears to be killed by a cave-in, though it is not actually shown dead. The device that it was building is shown coming online at the episode’s end, its purpose left unrevealed. The Loboan is revealed to have survived in “The Return”, and its device is used as part of Ghostfreak’s plan to block out the sun. In the next episode “Be Afraid of the Dark”, the Loboan’s transmitter explodes when Grandpa Max rams a space shuttle into Ghostfreaked’s corrodium projector, destroying it. It is unknown if the Loboan survived the explosion of the transmitter. Werewolf appears as an enemy in Ben 10: Protector of Earth in two variants: Fangface and Fangface Howler. [edit] Highbreed The Highbreed are an alien race that serve as the primary antagonists of Ben 10: Alien Force. They think of themselves as the highest lifeform in the universe, and consider other alien races as vermin. They are determined to cleanse the universe of them, with Earth as their next target. They are by no means subtle with their hatred for other races, as the Highbreed commander that fought with Ben continually insulted him with remarks like “filth” and                     and even exclaimed that Ben had “infected” him when Ben bit him. They are rather tall humanoid beings with white skin with four eye-like marks on their torsos, black hands and feet, and purple faces with four red eyes and no distinguishable mouths. The Highbreed Leader (voiced by Richard McGonagle) also has multiple wings with orange membranes, scythe-like protrusions on his abdomen, and purple-and-red markings on his abdomen. They use the DNAliens to do their dirty work, but like all other races still consider them to be vermin. While they have not shown any unique powers as of yet, they have remarkable physical prowess; a Highbreed Commander (voiced by Kevin Michael Richardson) easily overpowers Humongousaur. [edit] DNAliens The DNAliens are half-human, half-alien drones who serve the Highbreed. They are created by attaching a facehugger-like parasite called a Xenocyte to a human host, which alters the host’s genetic structure, mutating them into a DNAlien within hours . However, it is possible for the Omnitrix to separate a human from a Xenocyte. Their bodies are composed of a flock of tentacles that arrange themselves into a roughly humanoid form. The DNAliens can disperse this configuration to attack from long range. They can also spit a potent adhesive slime. This slime is strong enough that when it was used to pin Humongousaur’s arm to the floor, Humongousaur had to tear the floor piece off to free himself. They can disguise themselves as humans thanks to special masks which project a hologram over their bodies. The holograms that the masks project can be disrupted momentarily with a sudden flash of light, such as lightning. They can only survive in cold climates, thus they build weather control devices wherever they need to operate. Different VAs voiced the DNAliens: Richard McGonagle, Dee Bradley Baker, Diane Delano, and Paul Eiding

[edit] Neutral

These are neutral characters that are neither allies nor villains, or are not actually evil despite some         intentions.

[edit] Carl Tennyson

Carl (voiced by Dee Bradley Baker) is Max’s son, Ben’s father, Frank’s brother, Gwen’s uncle and Ken’s grandfather, who works as a gas line engineer and holds some resentment against his father for his work as a plumber (the sanitary kind), which had taken him too often from his family’s side. He learns about the Omnitrix and his father’s actual work the hard way when he is captured by Vilgax, but freed by Ben as Cannonbolt. He joins Ben, Gwen, and Max in fighting off Vilgax, setting off one of the gas lines and seemingly incinerating Vilgax. He and Max reconcile somewhat after that.

Carl makes his debut in Goodbye and Good Riddance. 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 descendent of the energy-based Anodite race, but he does not bear the “spark” to use such powers.

[edit] JT and Cash

JT and Cash are recurring bullies from Ben’s school. JT (voiced by Adam Wylie as a kid, Yuri Lowenthal in a brief cameo in “Ben 10 Returns”, and currently by Scott Menville as a teenager) is short and wears glasses, Cash Murray (voiced by Dee Bradley Baker and by Matt Levin as a teenager) is taller and has darker skin, compared to most. They are modeled after series producers Sam Register and Tramm Wigzell. The two take great pleasure in insulting Ben and suspending him by his underwear, though Ben returns the favor as XLR8 after coming into the possession of the Omnitrix.

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 spirit 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.

[edit] Julie Yamamoto

Julie Yamamoto (voiced by Vyvan Pham) is introduced in Ben 10: Alien Force as Ben’s new love interest. She first appears in the first episode, where Julie congratulates Ben on his soccer win, sparking Ben’s feelings.

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 Galvanic                attacks the area. Although Ben is initially desperate to hide his heroic lifestyle from Julie, he is eventually forced to come clean about it. Surprisingly, Julie is quite accepting of Ben’s Omnitrix-fueled exploits, and later helps him to repair a damaged            ship.

[edit] Sandra Tennyson

Sandra is Max’s daughter-in-law, Ben’s mom, Gwen’s aunt, Frank Tennyson’s sister in law and Ken’s Grandma. In Race Against Time, she wants her son to call her “Sandra”, suggesting that he have freedom. She sometimes goes against that, only to have her husband, Carl, stop her from it. She also appears in “Goodbye and Good Riddance” and is briefly seen in the Ben 10: Alien Force episode “Ben 10 Returns (Part 1)”.

Allies

[edit] The Galactic Enforcers

The Galactic Enforcers are a group of alien super heroes who act as law enforcement for the universe. The three of them seen in the series make their first appearance in the episode “The Galactic Enforcers”. Its current members include:

• Ultimos the Specimen Prime (voiced by Tom Kane) — The leader of his team, Ultimos is a Superman pastiche, complete with the same powers. His          is an ultra-strict copy of Superman, as well, as he follows the Galactic Code of Conduct too much to the letter. Earth chocolate is poisonous to his species (in essence, his kryptonite), causing his body to shrivel and turn brown. Ultimos The Specimen Prime and Alien X are similar.
• Synaptak (voiced by Greg Ellis) — Possibly the team scientist, Synaptak is a telekinetic, flying brain with an octopus-like lower body and a computerized face. He is initially jealous of Ben, as he has a crush on Tini but she loves Ben more, until he saves her life. He and Tini are hinted to have become much closer after that.
• Tini (voiced by Vanessa Marshall) — The muscle of the three, Tini is a female Tetramand, Fourarms‘ species, and hence has the same powers, as well as better mastery over them. Her name (pronounced “tiny”) might be considered a pass at humor, since she is approximately ten feet in height. She had a crush on Ben upon meeting him in Tetramand form (this persisted even after he had turned back to his original form), until Synaptak saved her life.

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 again in the ‘present day’ of the series past 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.

[edit] Tetrax Shard

Tetrax Shard (voiced by Dave Fennoy), dubbed “Hoverboard” in his first appearance for his namesake flying device, is a Petrosapien mercenary, hired by Vilgax in the episode “Hunted” to take the Omnitrix from Ben. Coincidentally or otherwise, he also happens to be one of the type of aliens in Ben’s Omnitrix. He has nearly impenetrable gray armor, a black helmet with a small, green triangle (presumably for sight) on it, and carries a large rifle. His Petrosapien physiology can manifest through the armor, allowing him to use his powers without removing it.

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. 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. 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. Where he will live in space remains to be seen, but it is highly likely that he would rather travel with Gluto than settle down.