Helen Wheels

Helen is a rogue Plumber kid, a Kineceleran who was adopted by humans. She is the younger sister of Pierce, as well as Manny Armstrong's partner and maybe his love interest.

History
Helen was originally part of a small team of "Plumber's helpers", young plumbers apprentices, with her brother Pierce and their friend Manny. However, they had little knowledge of the technology they used, and Pierce was at some point before their first appearance sucked in a Null Void Projector they had confused with a disintegrator weapon. Believing him dead, Helen and Manny continued the work, capturing many kinds of aliens they confused for criminals and sending them in the Null Void. Though part of those they captured were DNAlien, most of them probably were Plumbers kids, according to Ben.

After capturing a DNAlien in Plumbers' Helpers, their alien scanner points out three aliens which turn out to be Ben, Gwen, and Kevin. They believe them to be aliens so they set fire to a truck in hopes to see whether or not they are aliens. They then capture Kevin in hopes of leading Gwen and Ben to them. After a fight, Helen realizes they are not the enemy and that they have been sending plumber kids into the Null Void. Both Helen and Manny decided to go here in order to free those they had mistakenly trapped.

She then reappears alongside Pierce and Manny in Voided working with Max Tennyson trying to stop D‘Void, who turns out to be Ben's old enemy Dr. Animo. She contacted Gwen to find help. Then along with the help of Ben and Max they defeat him.

In War of the Worlds: Part 2, Helen, alongside Pierce, Manny and Grandpa Max to help Ben defeat the Highbreed threat, once the threat is over she becomes a pupil of Max.

In Season 3, she makes another appearance in Above and Beyond (she gets attacked by Echo Echo) where Ben is supposedly attacking Grandpa Max, But then it turns out to be a test and they are then told that because of their defeating Ben (as well as their heroic actions in trying to prevent the spacestation from hitting London) they are approved for training at the Plumbers' Academy.

Ben 10: Ultimate Alien
It was confirmed by Dwayne McDuffie that we will see the Plumbers' Academy in Ultimate Alien, with Helen enrolled in it.

She was also mentioned in Absolute Power: Part 1 by Alan, where he explained that her powers were stolen and killed by Kevin like he did to Manny, Pierce, Dr. Vicktor and Alan himself. She was revived and got her powers back after Kevin was changed back to normal.

Personality
Helen is smart, brave, kind, nifty and level-headed, though at times she usually tries to act rational and wise, making her mostly a mirror image of Gwen, as well as a older sister figure for young Plumbers such as Cooper and Alan. She is shown to be devoted to Max, willing to help him when he was seemingly attacked by Ben.

Helen share a specific love-hate relationship with her partner Manny. While Manny is usually hot-headed, aggressive and enjoys using violent methods, Helen usually prefers a more careful and less aggressive approach, causing occasional argument between them. On the other hand, she stated that he and her worked better as a team than with other Plumbers, and shows a true concern when seeing him injured or in danger. Though not proved yet, she might have a crush on him.

Abilities
Being a Kineceleran (or at least half-Kineceleran), Helen possesses powers and appearance similar to XLR8: her feet end with wheel-like appendices, making her able to move like a roller skater and giving her incredible speed. How exactly fast she can go has not be revealed, but she's shown being able to move fast enough to the same things as XLR8, such as reaching a wall or creating tornadoes.

Helen has also learned how to use her speed to her own and her team's advantage beyond the obvious; during the climax of Above and Beyond, in conjunction with Alan, Helen helped to restrict Ben as Humongousaur's movements and range of vision by using the airflow produced by her super speed to fan Alan's flames.

In addition to her powers, Helen is shown to be quite skilled with computers and technology, something who rather lacks to her partner Manny.

She also says in Above and Beyond that she works better with Manny.

Trivia

 * She is Pierce's adopted sister (as revealed by Dwayne McDuffie) though it is unknown how they met or what happened to their parents.
 * Her name is possibly a spin off of the 2nd armored division (Hell On Wheels)
 * Helen was shown to have some sort of a rivalry against Gwen as Manny on Kevin. But it hasn't come up in a while.
 * While the original cartoon's XLR8 had black claws for hands, she has blue hands and fingers, it might be because of human half or female Kinecelerans have these kind of hands.
 * Her name is a pun on wheels.

Ben 10: Alien Force

 * Plumbers' Helpers (first appearance)
 * Voided
 * War of the Worlds: Part 1
 * War of the Worlds: Part 2
 * Vengeance of Vilgax: Part 1
 * Above and Beyond