Kevin Levin (Classic)

By appearances a rebellious 11 year old, Kevin (voiced by Michael Reisz in his first appearance and Charlie Schlatter in his following ones, while he is voiced by Greg Cipes in Ben: 10 Alien Force) is actually 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. In the beginning of the episode Kevin 11 he is attacked by a gang after he destroyed their hang out under the 39th street bridge. 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 later 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. As a side effect, however, Kevin's ability to regulate this power is poorer than that of the Omnitrix itself, causing the energy to suppress his human form and forcing him to remain as an alien most of the time. As revealed in "Framed", Kevin blamed Ben for this, so he uses 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."[2] This form has:

Fourarms's head, body, left eyes, legs, and arm count Grey Matter's right eye Ripjaws's esca, gills, and teeth Upgrade's upper back and shoulders Stinkfly's wings Diamondhead's upper right arm Heatblast's upper left arm Wildmutt's lower arms and sense of smell Ghostfreak's lines XLR8's tail and speed After a brief battle with Ben as Fourarms, Kevin is shot off the Golden Gate Bridge by a laser fired by one of Lt. Steel's men, but due to Ripjaws's gills on his new form, he survives and recovers underwater.

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 aren't as good as his pure version (he quips that they're only one-tenth as strong, though this is likely not an accurate assessment)[3], and Kevin never exhibits his original powers in this form, nor those of Ghostfreak, Grey Matter, or Upgrade (The powers he can use are based on which aliens are used very often, hence he has Fourarms's body, arm count, strength, and appearance because Ben uses Fourarms the most). Kevin also seems to forget that he can fly and rarely uses XLR8's speed to his advantage, mainly relying on Fourarms's strength and endurance, Stinkfly's slime blasts, Diamondhead's crystals and Heatblast's pyrokinesis. Kevin 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, likely due to not being able to use his own abilities to absorb the traits of the new forms.

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 defeat and take the gladiator ship for his own (as revealed the enhanced commentary for "Back With a Vengeance").

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. It is revealed in the enhanced version of this episode that as he ages his human DNA is slowly restored.

In "Ken 10", Kevin returns after at least thirty years of imprisonment in the Null Void, having been set free by his son, Devlin. 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. 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". In this form, he now has:

A Heatblast-like skull-head, body, left wing and right tentacle, but black and yellow instead of red and yellow. A left tentacle that splits in the middle into a slim Fourarms arm and a tentacle with the markings of Upgrade and XLR8's tail Several grey tentacles (similar to the tentacles of the flying aliens featured in "Truth" and "Back With a Vengeance") protruding from his lower body. Wildmutt's arms Stinkfly's wings (though only the right wing has the same pattern) Fourarms's legs Benwolf's sonic howl In addition the powers in his mutant form, his form was able to withstand a pummeling from Way Big without and signs of injury.

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. It is unknown why Kevin hates Ben due to the fact Kevin is on Ben's side in Ben 10: Alien Force. In the enhanced version of Ken 10, It is stated while it is a possible future for Kevin, it's not an exact and does not have to happen. So he is given a second chance and does not blow it.

In the video game Ben 10: Protector of Earth, Kevin only appears, surprisingly, 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.He now has a green modified Plumbers car and apparently a crush on Gwen, though he won't admit it. Although reformed, Kevin does have moments of relapse including one point in which he tried selling the Rustbucket for alien technology. It is revealed that Kevin's last name is Levin, a play on Kevin 11.[4]

In Ben 10 Alien Force, 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).

Kevin reappears in Ben 10: Alien Force, initially brokering a weapons deal between the Forever Knights and the DNAliens. After Ben interrupts the deal and captures Kevin, in the process preventing him from being paid, he joins Ben and Gwen in their quest. Though he only do so to get his money back at first, Magister's death convinces him to genuinely assist them. He has returned to his human form and his power has been altered, allowing him to take on the properties of any solid object he touches (similar to Marvel's Absorbing Man) instead of just draining energy. He now has a modified Plumbers car and apparently a crush on Gwen, though he won't admit it. Kevin is something of an anti-hero in the series; while he wants to help, he is not above stealing treasure from the Forever Knights when the opportunity presents itself, and tries to sell the Rustbucket for alien technology.