Ragnarok

Ragnarok is a character introduced in season 3 of Ben 10: Alien Force. He is notable for being the one who murdered Devin Levin, Kevin's father.

Backstory
According to Max's flashback, Ragnarok was originally a powerful and dangerous alien criminal from unknown origin, who possessed a ship able to drain energy from suns, destroying them in the process (something reminiscent of The Fallen's plan in the movie "Transformers: Revenge of the Fallen") ~Ew, dude that movie sucks, what the hell?~ As he was about to absorb Earth's sun, Devin Levin and Max Tennyson successfully stole the key for his device. Ragnarok succeeded in catching their ship, and threatened to kill Max if Devin wouldn't tell him where the key was. When Devin declined, Ragnarok attempted to kill Max, but Devin put himself between them, and was fatally wounded instead of Max. Furious, Max used the element of surprise to send Ragnarok in the Null Void, where he was taken in custody.

Ben 10: Alien Force
Ragnarok appeared in Vendetta, where he escaped from his Null Void prison and the Null Guardians and arrived on Earth. After he trashed Kevin's house in order to find his key, Kevin's mother revealed him what exactly happened to his father, causing the young Osmosian to start looking for Ragnarok in order to get revenge. Feeling worried for Kevin, Ben and Gwen learned exactly who Ragnarok was from Max, and attempted to help Kevin, only to be asked by him to stay out of his way. Eventually, Ragnarok got the key back, and attempted to use it to activate his machine, but Kevin successfully infiltrates his ship, and destroys the ship's command, causing the device to be damaged and the air tank to break open. Ragnarok then begs Kevin for help, stating that his father was a Plumber and would never have let him die. Instead, Kevin just took the key from him and left him be sucked into cold space, seemingly causing his death.

Ben 10: Ultimate Alien
It's currently unknown if Ragnarok will appear again as he is thought to be dead, though Dwayne McDuffie stated he believed it would be a good idea.

Powers and Abilities

 * Superhuman Strength & Durability
 * Agility
 * Solar Energy BlastsRagnarock_face.jpg

Trivia

 * Ragnarok is the end of the universe in Norse Mythology. It’s stated that it’s where the gods and giants will die and the universe will be reborn.
 * He is one of a few Ben 10 villains known to have committed murder/genocide (the others being Vilgax, Aggregor, Adwaita and Urian). Because he was responsible for killing Devin Levin, he is Kevin's sworn arch nemesis (basically he is Kevin's Vilgax, though Darkstar may also be considered this).
 * He appears to be the same, or similar, species to Sunder and the Vreedle Brothers.
 * Though the blast that hit Devin did kill him, Ragnarok was not intentionally trying to kill him. He was trying to kill Max.
 * When Kevin introduces himself he makes an oblique reference to the Princess Bride, saying "My name is Kevin Ethan Levin, you killed my father, prepare to die," echoing the famous quote of the book and movie, "My name is Inigo Montoya, you killed my father, prepare to die," (repeated). According to Dwayne, Mrs. Levin read the book to Kevin as a child.
 * When asked who would buy the energy of the Sun, Dwayne McDuffie said, " Maybe you'll meet them, the sun is a very large amount of energy though”.
 * Ragnarok teleports the same way as Azmuth does.