She was the reigning monarch of Cluster Prime and leader of the Cluster, and is still one of XJ-9's most recurring foes. She was voiced by the late Eartha Kitt in all of her appearances except in Around the World in Eighty Pieces (2004) and as Violet and Vicky in Queen Bee (2006) where she is voiced by Cree Summer. A cunning and cruel robot queen, Vexus (voiced by Eartha Kitt) is bent on the enslavement of the human race. She is the main antagonist of the series.

Vexus and Dr. Wakeman have been opponents for what must have been quite some time, and Vexus was likely the inspiration for Jenny's creation. XJ-9 typically can outwit and outperform Vexus, but regardless, Vexus has the resources of an entire planet to call upon. Occasionally she does gain the upper hand, typically through trickery and sabotage.

She possesses the ability to transform, but typically for means of disguise, compared to the multitude of battle forms that Jenny typically uses. Her known forms are as the sneaky android, photographer in "Hostile Makeover" (2002), the robot nurse named Vee in "Tradeshow Showdown" (2002), a flirtatious teenage robot girl named "QT-2" (pronounced "Cutie 2") in "Designing Women", and even the transfer students Vicky and Violet in "Queen Bee" (2006).

In Escape from Cluster Prime (2005), it is revealed that Queen Vexus has a daughter named Vega. During the course of the movie, Queen Vexus is dethroned by Jenny and Nora Wakeman (with Sheldon's help) and Vega takes the leadership of Cluster Prime for her own. Despite fleeing from Cluster Prime, Vexus returned in the series afterward in “Trash Talk” (2006), and in "Queen Bee" (2006), in which she donned a new look. Vexus' physical appearance is that of a green- and yellow-striped insectoid alien robot. She has long striped legs with high heels, a black bottom and a yellow top. She has large black arms and hands with green sleeves attached to them. Some parts of her body, like her belly and upper arms are not covered by armor, but show her black robotic body. She has a small insectoid head with long curved antennae-like features. She has long green and yellow striped “hair” that resembles the headdress of an Egyptian pharaoh, a crown-like feature with an orb on it, and clear white wings. She has long eyelashes, red lips, and sharp fangs.

Where all the description came from: https://teenagerobot.fandom.com/wiki/Vexus