Kevin Ethan Levin, Kevin, is a seventeen year old (eleven in Ben 10, sixteen in Ben 10: Alien Force, seventeen in Ben 10: Ultimate Alien-present) Osmosian/Human hybrid with the unique ability to absorb any type of matter or energy through his body at will in order to utilize it in various ways. Kevin became a threat during the first show from absorbing energy, an action that warps an Osmosian's mind as a result. After accidentally absorbing some energy and demolishing his family's house, Kevin's warped mental state convinced him that his stepfather, Harvey Hackett, had convinced his mother to throw him out. Running away from home, he eventually ended up in New York City, making a home for himself in the subway tunnels. He befriends Ben in their first encounter in order to use the Omnitrix's power to take out his anger on everyone who treated him like a monster because of his abilities. However, absorbing too much of the Omnitrix energy causes Kevin to turn into a chimeric hybrid of the alien forms and swears revenge on Ben for it. Eventually, Kevin ends up at the Null Void where he manages to regain his human form and fully master his abilities under the guidance of an inmate. He eventually manages to escape and became involved with the intergalactic black market. However, his involvement during the Highbreed invasion causes him to team up with Ben and Gwen, leading him to live his dream of being a Plumber like his father, reconciles with Ben, and starts a romantic relationship with Gwen over time. Though able to start on a new leaf, Kevin still acted out of his own interests at time and has trouble forgiving others. During Vilgax's challenge to Ben, Kevin accidentally mutated into a living colossus composed of steel, Tadenite, concrete, and wood.This space of time showed Kevin's insecurities about his relationship with Gwen. During his second mutation he gained the ability to turn his limbs into makeshift weapons. When the Omnitrix was destroyed, Kevin reverts back to normal, retaining his ability to shape shift after copying matter, as well as gaining the ability to secrete a liquid form of whatever material he has absorbed or manipulate the material when he is touching it. Ben 10: Ultimate Alien features more about Kevin's past (from the original series to be precise). Kevin still has the ability to change his hands into different weapons even after he returned to normal in Alien Force. During the events of Ultimate Alien, Kevin is forced to absorb the Ultimatrix's energy in order to stop Aggregor, sacrificing his mental stability in the process, and became insane as a result and a monstrous combination of Ben's newer aliens. After absorbing the energies in Aggregor, Kevin goes on a revenge spree against anyone who wronged him. However, unlike when he was eleven, Kevin is more of an anti-villain rather than a true villain, and has shown that he still retains some of his heart and humanity despite going insane after absorbing the Ultimatrix's energy. This is best seen in "The Enemy of my Enemy", when he spared Gwen's life instead of killing her, saying: "The only reason you're alive is because of what you used to mean to me". In the two-part episode "Absolute Power", Kevin had absorbed the powers of Alan Albright, Manny, Helen, Pierce, and Doctor Viktor. Gwen tries to reason with him which occasionally failed, even the reasoning from Grandpa Max and Kevin's stepfather didn't go through, in a last stand in Los Soledad, Ben as Ultimate Echo Echo, finally managed to bring him down;showing uncharacteristic coldness.However,Cooper was able to cure Kevin, resulting in Gwen and Kevin sharing a passionate kiss.