Transformers is a highly popular franchise created by Hasbro, beginning originally as a line of poseable, transforming action figures and vehicles. In the years since the toys were first created, Transformers has expanded into many media formats, including animated cartoon shows, movies, board games, video games and comics.
Transformers are a unique race of robotic aliens that dwell on the mechanical planet of Cybertron. Once a peaceful society, Cybertron was thrown into civil war when the Decepticons - a militant faction - rose up against the old regime and declared themselves the would-be rulers of Cybertron and, eventually, the entire universe. Under the command of their maniacal leader Megatron, the Decepticons marched across Cybertron and slaughtered the most of the peaceful population. Eventually, a resistance group formed known as the Autobots, led by the noble Optimus Prime. They battled against the Decepticons for centuries, the constant fighting resulting in their planet being depleted of its energy and reduced to a wasteland. With Cybertron completely ravaged, both the Autobots and Decepticons would leave the planet in order to find new energy sources so that they could win the war and rebuild their world. Both factions would spread out across the galaxy, bringing the war to other planets - including Earth.