Cylon (reimagining)
Cylons are a fictional artificially-intelligent "species" envisioned in the Battlestar Galactica science fiction series and related franchises. Originally created to serve human needs like other machines, a series of events involving the transfer of a human's consciousness into a Cylon's neural network led Cylons to evolve into sentient, self-aware beings. The original Cylons were purely mechanical.
The Cylon was reimagined in the second Battlestar Galactica television series and its prequel Caprica. The first configurations (Centurions) were robots. Others were cyborgs whose different configurations incorporated biological elements, including some that were nearly indistinguishable from humans.
Background
The Cylons had different origins in the Battlestar Galactica reboot (BSGr) and Caprica. In BSGr they were created thousands of years earlier, and fought a war against the Thirteenth Tribe on Earth. This origin is at least mostly compatible with their origin in the original series. In Caprica they were created by Zoe Graystone and her father Daniel Graystone, owner of Graystone Industries.