The Decepticons are a militant faction of Transformers from the planet Cybertron. Founded and led by the former gladiator Megatron, the Decepticons' original purpose was to bring new order to a corrupt regime on Cybertron and elimate their society's unfair caste system. Over time, however, the warmongering Decepticons became more concerned with strengthening Cybertronian society through aggressive expansion and sought to conquer not only their home planet, but the entire universe. Over the course of The Great War, millions of Cybertronians perished and their planet was all but depleted of energon. When the Autobots left Cybertron to find new energy sources, the Decepticons pursued them across the galaxy, bringing the war to Earth and many other worlds. Since discovering Earth, Megatron and the Decepticons have concentrated all their efforts on usurping the planet's resources and destroying humanity. Their attempts at conquest are repeatedly thwarted by Optimus Prime and the Autobots, who have allied themselves with the humans to protect the Earth from destruction.