The Cybermen were a race of cybernetically augmented humanoids in the Doctor Who Universe. They varied greatly in design, with different factions originating independently by parallel evolution on planets throughout time and space, including Mondas, Telos, an alternate Earth, Planet 14, and Marinus. Some Cybermen were born out of an instinct to survive, others hungered for immortality because their civilizations were dying out and they wanted to survive, and some were born from the intent to upgrade themselves and everyone around them.
Despite their many different origins, there were similarities between most groups of Cybermen. For the most part, they lacked individuality or names, and had no emotions, viewing them as a weakness. They frequently attempted to physically and mentally re-engineer humans and other humanoids into Cybermen, via a process called "cyber-conversion".