Android 17 is the younger twin brother of Android 18 and Dr. Gero's seventeenth android creation, designed to serve Gero's vendetta against Goku. Despite his interests not initially deviating from this expectation, Android 17 takes it upon himself to kill Dr. Gero, who is uncooperative with Android 18's curiosity in activating Android 16 and deemed inferior by 17. Android 18 is the older twin sister of Android 17 and Dr. Gero's eighteenth android creation. Their goal is to commit mass genocide.