The Cybermen Edit
The Cybermen originate from the earths twin planet mondas and were originally like humans but then started to replace their body parts with computer chips, plastic and metal. They removed all their emotion as they consider emotion as a weakness. The first cybermen were bulky, still had human hands and cloth like faces. They Consistently upgraded themselves. All that is not cybermen and is human is upgraded (turned into one of them) and everything else that is not compatible is "deleted".