Sunder

Sunder is an alien bounty hunter that first appeared in Single-Handed.

Alien Force
He was sent by Vilgax to pursue Ben and to try to remove the Omnitrix from Ben by using his energy axe to bring to his master. The result inadvertently sent Ben to the Null Void, but only left Ben's left hand on Earth, where the hand itself managed to escape from Sunder and knock him out before leaving to find help.

When the hand was found by Julie, she brought it to Gwen and Kevin. They fought to keep Ben's left hand from falling into Sunder's clutches. When Kevin invented a machine that could bring Ben back, it was a success except that Ben's left hand is now in the Null Void. As Sunder charged toward the group, Kevin activated the machine once again and restored Ben's left hand to his body. However, it also sent Sunder to the Void, surrounded by its hostile inhabitants.

Ultimate Alien
Sunder returned in the first episode of Season 2, The Transmogrification of Eunice, where he was on a mission to retrieve the Unitrix, which has taken the form of a girl named Eunice. At first, Ben and his team thought Sunder wanted Eunice for himself, but at the end, it is revealed that Azmuth hired him to bring Eunice back to him in exchange for being released from the Null Void. Ben convinced Azmuth to let Eunice have a normal life and be one of his assistants as he always needed help tending Primus. When Azmuth, Eunice, and Sunder left, Sunder asked to Azmuth if he is still getting paid even though he had failed.

Omniverse
Sunder returned in Have I Got A Deal For You, having reverted back to his evil ways, and battled Shocksquatch in Undertown. As before, he was after Ben's Omnitrix, but was defeated. His axe is now connected to a whip and his hair is bigger. He wears mask and has spikes on his shoulders and knuckles. During Special Delivery, he and several other villains try to get the Dwarf Star in Ben's possession but was again defeated.

Powers and Abilities
He has an axe which is able slice through things. It can also send whatever it slices to a different dimension when it strikes something such as the Prototype Omnitrix, as he was able to send Ben (minus his Omnitrix hand) to the Null Void. He also uses a Hover Board for transportation. He has many gadgets inside his hover board, and possesses enhanced strength sufficient enough to hold his own against Ultimate Cannonbolt, Kevin, Gwen and Eunice all at once. It is unknown whether these gadgets are used for combat or sells them for profit. He is also shown to be durable, able to withstand repeated injuries such as being able to withstand Diamondhead's shards at point-blank to the face, though it still causes him discomfort.

In The Transmogrification of Eunice, he possessed a powerful blaster-pistol which he revealed he had obtained on Galvan Prime.

Ben 10: Alien Force

 * Single-Handed (first appearance)

Ben 10: Ultimate Alien

 * The Transmogrification of Eunice (first re-appearance)

Ben 10: Omniverse

 * Have I Got a Deal for You (first re-appearance)
 * Special Delivery

Video Games
Sunder appears in Ben 10 Ultimate Alien: Cosmic Destruction for all consoles. He appears in Paris, and tries to take the second piece of the Potis Altiare after Ben defeated the Vreedle Brothers. After two failed attempts on Ben's life, Sunder fights Ben on the Eiffel Tower, but is soundly defeated by Ultimate Swampfire and thrown off the tower.

Trivia

 * He's similar to Red X in Teen Titans status wise as he is only looking out for himself and is neither a villain or a hero as show that he was fiercely chasing Ben in Single-Handed but didn't want anything to do with Ben in his next episode. It was only because Ben and his team interfered that he fought them similar to how Red X fights the Titans only when they interfere with his work.
 * He resembles Terrax from Marvel Comics.
 * He uses a Glider just like Green Goblin and The Hobgoblin characters from Marvel Comics.
 * Ironically, Azmuth (who is one of Ben's allies) had to hire Sunder, who is one of Ben's enemies.
 * It is said by Dwayne McDuffie he was hired by Azmuth because he specializes in retrieving unique objects, and the Unitrix could have transformed into *any* sapient creature in the galaxy. Azmuth needed someone resourceful and tough. He is also considered the best.
 * Sunder is another word for "steal by any means necessary" which is a reference to his bounty hunting job.
 * The form of his head, and his hair style in Omniverse, resemble V.V Argost from The Secret Saturdays.
 * He resembles Lobo from DC Comics, because both characters are bounty hunters, have long hair, similar shadings around their eyes, both are not good or evil, and suners power axe in OV is similar to Lobo's chained hook.