Replying...
Intro. the decepticons are the good guy, and the autobots are the bad guys. The autobots are led by the tyrant Optimus. The decepticons are led by the kind prime Megatron. Megatron and Optimus used to be best friends until Megatron brought Optimus to the council to discuss the caste system and Optimus showed his true colors. Demanding he be give the matrix of leadership Optimus tried to take it by force, when Megatron defused the situations he was rewarded with the true matrix of ledership and named Megatron prime. Optimus? He was furious, so much so he waged war against Megatron and called his group the autobots stating that they were superior and deserved to rule cybertron. Megatron led his own group in order to attempt to free cybertron. Optimus named then decepticons to try and strike fear in civilians but Megatron embraced it, saying that the decepticons fought against the deceit that Optimus was feeding. So a war began.

Transformers shattered glass

@Redwing