Myaxx

From Ben10versepedia

Azmuth's assistant, Myaxx is a Chimera Sui Generis, like Vilgax. She encoded her own DNA into the Omnitrix in place of Azmuth's DNA signature, in order to take credit for its creation and as revenge for his unwillingness to give her any credit. She also created the cloaking field that hides the planet Xenon, where Azmuth maintains his compound. She first appears in "Ben 10: Secrets of the Omnitrix."

Having spent some time as Azmuth's assistant, Myaxx somehow ended up on the prison facility of Incarcecron. When Tetrax and the Tennysons arrived there in search of her master, Ben--due to her concealed face and the lack of many superficial differences between male and female Chimera Sui Generis--mistook her for Vilgax and transformed into Upchuck to attack her. After she learned who Ben was, she joined the crew and revealed that she had not actually created the Omnitrix, but had aided Azmuth in doing so. It was also because of her that Tetrax was forced to reveal to Ben that the Omnitrix's self-destruct would destroy the entire universe instead of just him.

Cowardly and self-centered, Myaxx still managed to prove helpful, placing a device on the Omnitrix to keep it from releasing any more energy discharges. She then aided Tetrax and the others during subsequent battles with Vilgax, and she even participated in the final confrontation with him. Afterwards, Azmuth invited her to relocate with him to a new planet, and she agreed despite his curmudgeonly refusal to offer her any respect.