|This article about a fictional alien is written from a real-world perspective, rather than an in-universe perspective. It is therefore not in accordance with the editing conventions and must be rewritten.|
Human Form Edit
Kevin's physical appearance has changed from a 11 year old to a 17 year old. However, he retains some recurring characteristics, such as shoulder-length black hair, somewhat pale skin, and dark brown eyes.
As a kid, Kevin wears a black T-shirt, black arm bands, brown, blue or grey pants, all-black or black-and-red shoes, and a padlock necklace.
As a teenager, Kevin generally wears a black T-shirt, blue pants, and black shoes, and has his hair styled into a choppy mullet. He alternatively wears a white shirt, a blue short-sleeved jacket, blue pants, and black shoes.
Prior to moving out of Bellwood, Kevin's prominent outfit consisted of a black shirt, a long sleeved grey shirt, and blue wholesters. He also wore a padlock necklace similar to the one he wore when he was younger, but marked with an "11". During his sequent visits, Kevin gains a few chin whiskers, some stripes on his gray shirt, and a cross-shaped scar on his chin.
Mutated Forms Edit
Kevin as undergone multiple mutations, most of which involved using his powers on the Omnitrix. His first mutation occurs when he absorbed some of Heatblast's DNA. He temporarily became half-Pyronite, with his left arm and lower body remaining unaltered, and his upper right chest, head, and right arm resembling that of a Pyronite.
Kevin later absorbed some of Four Arms' DNA and temporarily became half-Tetramand. While his hair remained unaltered, he gained red skin, crooked teeth, and large arms with black fingernails.
Kevin 11 Edit
Kevin's first major mutation occurred at age 11, when his powers got out of control. Kevin was stuck in this form until a Null Void prisoner named Kwarrel taught him to control his anger and master his powers, resulting in Kevin reverting to his human form.
Kevin 11 had Lepidopterran wings, a Kineceleran tail, an Ectonurite eye track on his chest, and an upper back resembling a Galvanic Mechamorph. His head consisted of Kevin's hair and ears, two left eyes similar to those of a Tetramand, a Galvan-like right eye, and the lure, teeth, and gills of a Piscciss Volann. He retained the same pants that he had worn before his transformation.
Mutant Kevin (young) Edit
Kevin's second major mutation occured when he (at age 12) used his powers on the Omnitrix during a fight with Eye Guy. However, he was restored to normal after being knocked out by Argit before being taken back to the Null Void by the Amalgam Kids.
12-year-old Mutant Kevin's appearance was similar to, yet different from Kevin 11. His face retained Kevin's structure and hair, but had skin colored in two different tones of green, a Loboan-like right eye, an Opticoid-like left eye, a Gourmand- like mouth, and a head fin and eyes on his chin similar to that of a To'kustar.
His arms had lower parts resembling an Arburian Pelarota's and upper parts resembling a Transylian's with red Opticoid eyes, small spikes, and fingers resembling Florauna tentacles. He also had Splixson legs, Florauna eggplant bombs, and a large Gourmand tail. He wore Kevin's pants and a Thep Khufan crown.
Mixed Material Kevin Edit
Kevin's third major mutation occured when he was 16 years old, when Ben's attempt to hack the Omnitrix backfired and the device itself overloaded, releasing a feedback that altered Kevin's DNA with those of various mater-related aliens in the Codon Stream. However, he was later turned back to normal when the Omnitrix was destroyed, due to the device's energy having previously kept him in that form.
Unlike his other mutations, Kevin retained his original frame, and instead had his body made out of common elements. The right half of his face, the left half of his chest, the upper right half of his chest, part of his back, and his left arm were made of concrete, the lower right half of his chest, part of his back, his stomach, and his right arm were made of metal, the left half of his face was made of Taydenite, and his legs were made of wood.
Ultimate Kevin Edit
Kevin's fourth major mutation occured when he (at age 17) absorbs DNA from the Ultimatrix to stop Ultimate Aggregor from absorbing the powers of a newborn Celestialsapien. He easily drained Ultimate Aggregor's powers, reverting him back into his original form, and then left the Forge of Creation. However, he was later cured thanks to the efforts of Ben, Gwen, Cooper Daniels, and Darkstar.
Ultimate Kevin's composition was more complex than his earlier mutations from his youth. His face mostly resembled an Aerophibian's, but with Kevin's hair, a patch around the right eye resembling an Evolved Vaxasaurian, and a jaw similar to that of an Evolved Arachnichimp but with an interior resembling that of a Sonorosian. His torso resembled a Vaxasaurian's, but the backside was colored like an Aerophibian and had a set of Necrofriggian wings.
His right arm mostly resembled a Petrosapien's, but with two Crystalsapien crystal spikes on the shoulder and a Biosovortian-like claw. His left arm mostly resembled a Methanosian's, but with a Biovosortian spike on the shoulder and Appoplexian-like claws. He had an Aerophibian-like right foot and an Appoplexian-like left foot.
Mutant Kevin (teenage) Edit
Kevin's fifth major mutation occured when he (at age 17) used his powers on the Omnitrix during a fight with Gutrot. However, he willingly reverted to his human form after betraying Servantis and freeing the Amalgam Kids from his mind control.
17-year-old Mutant Kevin's face resembled that of a Gimlinopithecus, but with red eyes, Kevin's hair, a Vladat-like mouth, a crest resembling both a Gimlinopithecus and an Insectoid, and Conductoid antennae.
He had an upper right arm resembling a Segmentasapien's, an upper left arm resembling a Galilean's, a lower right arm resembling a Pturbosaurian's, and a lower left arm resembling an Atrocian's but with sharper claws. His torso mostly resembled a Gimlinopithecus's, with pieces of both Segmentasapien and Galilean near the shoulders.
Monster Kevin Edit
In an alternate timeline, Kevin once turned into an amalgam of all 11 of his Antitrix aliens by Charmcaster in order to fight Ben and Gwen. However, he returned to his original form after being tricked into using his fire breath to burn Charmcaster's spell book beyond repair.
His head resembled Kevin's but a goatee resembling Quad Smack's, and a mane resembling Bashmouth's. He had purple skin, and a torso resembling Quad Smack's but with six arms rather than four.
His upper left arm resembled Crystalfist's, while his upper right arm was a purple version of Hot Shot's. His middle left arm resembled Thornblade's while his middle right arm was a purple version of Bootleg's. His lower left arm resembled Undertow's, while his lower right arm resembled Dark Matter's. He also had Wreckingbolt's back, purple versions of Skunkmoth's wings, and Rush's tail in place of legs.
In an alternate timeline, Kevin is acts as both an enemy and an ally to Ben. Unlike his primary counterpart, this Kevin an ordinary human equipped with a replica of the Omnitrix that he generally uses to fight Ben out of pride and jealousy.
- In the original continuity, Kevin's padlock was a spoil from the first crime he committed as a child, which was stealing a bike and using it to run away from Bellwood to New York. In the reboot, the padlock contained a tracker that was placed there by the Forever Knight before Kevin destroyed it in the episode "Franken-Fight".
- According to Duncan Rouleau, the idea of Kevin having his own Omnitrix in the reboot was a repurposing of an unused concept intended for the original series.
- According to Derrick J. Wyatt, the creators of the original series intended for Kevin to be a mutant.
- Kevin was the first non-Tennyson family member that Ben shared his secret (i.e. the Omnitrix) with.
- Kevin got this X-shaped scar due to being whipped by Swampfire. His counterpart in Ben 10,000's timeline also has a scar of the same shape.
- As the Antitrix aliens have been confirmed to be "cross-contaminated" hybrids, Monster Kevin is technically comprised of 23 different species, including human, Tetramand, Pyronite, Kinecerlan, Subsapien, Arburian Pelarota, Galvanic Mechamorph, Galvan, Cascan, Florauna, Lepidopterran, and Bashmouth's Species.
- Due to some of Monster Kevin's body parts having a more purplish coloration, Bootleg's arm more closely resembles Upgrade's.
- Monster Kevin was literally based on Kevin's amalgam forms from the original continuity especially the one featured in the original series and the other one featured in a flashback in Weapon XI Part 2.
- Monster Kevin was also the second amalgam form to appear in the reboot after Amalgam Ben from Riding The Storm Out.
- Kevin's equipment The Anti-Trix was similar to The Ultimatrix from the original continuity.
- Both were created by the villains.
- Both makes the aliens powerful in combat.
- Both also have red as their primary color.
- According to Duncan Rouleau, Kevin and Charmcaster were created to foil Ben and Gwen based around their youths. If Gwen recieved a spinoff series, Charmcaster would have joined her side just like Kevin joined Ben's side in Alien Force.
- At the end of Weapon XI Part 1, Kevin wore these clothes which they're the same ones his future self wore in the original series.