For pretty much ALL of Transformers history, Megatron/Galvatron, Unicron, The Fallen, whoever, was the big bad of a series/film. The Decepticons and their leaders have always been the main villains. Only when the fiction was told from the Decepticon's POV were Autobots the villains. Even the humans have been villains, but far less than Autobots ever have. Animated broke the mould - something done rarely in Transformers - and introduced an Autobot who made Optimus Prime and his team's lives living hell. Sentinel Prime. He openly acted as an antagonist throughout the series. He took it a step further in the third season, when he dealed illegally with a Decepticon for Decepticon prisoners, attempted to commit murder of two Cybertronians, allowed one of said prisoners to escape with loads of goods and weapons when the prisoner was IN firing range, and deliberately fired upon an Autobot war veteran against the Autobot Council's orders. While the main plot of the third season was over control of Omega Supreme, Megatron took another leave of abscence from the show... leaving Sentinel to appear far more often then Megatron did so. I began mulling this over sometime ago... and came to a theory. Sentinel Prime was the main antagonist of Animated's season three. Thoughts? I don't think multiple choice is neccesary.