Dr. Gero

Dr. Gero is one of the bosses in Dragon Ball Z: Kakarot.

Cell Saga
Though he introduced himself as a creation of Dr. Gero's known as Android 20, he is in fact the mad scientist himself, who modified himself in order to achieve immortality. After the Red Ribbon Army's defeat at the hands of Goku. Dr. Gero vows to seek vengeance against the boy. He is approximately equal in power to that of Android 19. He has created many complex and high-functioning androids, but his failure to adjust Android 16's more peaceful personality, as well as his inability to control Androids 17 and 18, proved that he was still inexperienced with artificial intelligence. When creating Android 19. he was finally able to return to a synthetic model that was combat ready and obedient