Dr. Gero, also known as Android 20, is a brilliant but twisted scientist and former member of the Red Ribbon Army in the Dragon Ball Z series. He is the creator of many androids, including Androids 17 and 18, and is a key antagonist during the Android Saga. Driven by revenge against Goku for the defeat of the Red Ribbon Army, Dr. Gero transfers his own brain into an android body, making himself a formidable threat. His inventions have lasting impacts on the series.