Dr. Myuu

Dr. Myuu is a major antagonist in Dragon Ball GT originally serving as the secondary antagonist of the Black Star Dragon Ball/Baby saga only to become the main antagonist of the Super Android 17 saga.

Trivia

 * Although Dr. Gero was the one who originally came up with the idea to use Android 17 and Hellfighter 17 to open the gates of Hell to have him and Dr. Myuu escape and then have them merge into Super Android 17 to use him to take over the world Dr. Myuu is the Super Android 17 saga's main antagonist because he had bigger plans.