Dr. K

Dr. K sitting right next to a container with Solex.

Doctor K is a former scientist at RobixCorp and serves as the primary antagonist of the entire series, alongside with the Alien in Season 1. His right arm is cybernetic and can transform into a Solex Extractor, and possibly other tools as well.

His robotic minions are Kolossal/Scavenger, Krab, Klawber, Katastrophe and Kannon. In Episode 13, his entire HQ turns into a massive robot, Kulminator, which ends up being destroyed. In Season 2 Dr. K created a robot called Kilobot/Demonix, which is able to take data from other robots in his plot to take all of Cubix's data.