Thinking more about this movie's take on the Aligned backstory lore of "Optimus and Megatron were once friends as close as brothers before falling out and becoming bitter enemies", a thought crossed my mind tonight about that backstory in general. Awhile back, there was some talk about this backstory in the Post Pictures thread, about how it was seemingly born out of a throwaway line in the 2007 movie, in which Optimus called Megatron "brother". But after seeing TF One, I got thinking about this notion and how the Exodus novel first established that the falling out between Optimus and Megatron was because of Optimus being chosen to be the next Prime--first by the High Council and then by Cybertron's Core--instead of Megatron. This left Megatron feeling embittered, betrayed, and jealous of Optimus. The more I thought about this, the more I realized how familiar this sounded. Then it hit me where I'd seen the same broad strokes of this story told before: Robots in Disguise 2001! In that series, Optimus Prime was chosen by Vector Sigma to be the leader of the Autobots and the bearer of the Matrix, which left his literal biological brother Ultra Magnus feeling embittered, betrayed, and jealous of Optimus, feeling that he should have chosen to bear the Matrix instead of Optimus. It's very possible that, when putting together the Binder of Revelation, Rik Alvarez and his team came up with the new backstory for Optimus and Megatron by taking direct inspiration from that initial brotherly feud between RID01 Optimus and Magnus, with Megatron swapped in for Magnus and made less a literal brother and more just a metaphorical one.