Helen Wheels is half human, half Kineceleran (XLR8's species) and Pierce's adoptive sister.
She was originally part of a small team in the episode "Plumber's Helpers", young plumbers’ apprentices, with Pierce and their friend Manny. Helen is smart, brave, kind and level-headed, though at times she usually tries to act rational and wise, making her mostly a mirror image of Gwen, usually prefers a more careful and less aggressive approach, causing occasional argument between her and Manny, sharing a love-hate relationship with him, and she might have a crush on him. Helen has quite skilled with computers and technology and has the same abilities as XLR8, as well as a visor, though it only covers her eyes.
Helen and Manny used to hunt all sorts of aliens they confused for criminals whom they would throw into an old Null Void projector, which they've mistaken for a disintegration weapon. Manny convinced Helen that Ben, Gwen and Kevin, were DNAliens, but the confusion is eventually cleared up after Ben proves that the Null Void projector wasn't a disintegration weapon. To rescue those they may have falsely imprisoned, because part of those they captured probably were Plumbers' kids, Helen and Manny travel into the Null Void. Later, Helen telepathically contacts Gwen for help against Dr. Animo, which Ben provides.