Rick and Morty will be back to have more adventures through time and space this fall. One question that fans have has around the series for a while now is the true motivations and identity of the Evil Morty that is running amok in the series. He made some bold leaps in power last season and looks to be gaining ground as the main antagonist of the series now that he's eliminated all of his opposition.
A Redditor has a bold theory for why this evil version of the Morty that fans have grown to love over the series' run is so important. To summarize, because there is a lot of ground to cover, there are multiple copies of Rick and Morty across infinite timelines. In the C-137 universe, where the main story occurs, the Morty the audience knows is put onto a course to defeat the Evil Morty because he's becoming more like his grandpa Rick.
Evil Morty and the main version aren't just two different reflections of the same character, they are literally the same person from a split timeline in this theory. Spending all that time with Summer and Morty after the end of Season 1 helped improve the relationship between Rick and his grandson a lot. In turn, this provided him with the skills to become more resilient and capable (read: more like Rick).
Now, the doppelganger is out for revenge against the Rick that he feels abandoned him back then and to prove that he's the best version of a Morty that ever existed. I know that entire explanation is a long winding road, but it does seem to track a little bit, or at least as much as these discussions about parallel universes and time travel can. The thought of Rick Sanchez trying his hardest to evade authorities and protect his grandson is touching because of the scientist's prickly nature.
In the lead-up to season four, Rick and Morty actually started to lean into all the fan speculation about Evil Morty with a post on the show's Twitter account. The text read: "Black and white and dread all over. @adultswim." This could be Justin Roiland and company trolling, or it could possibly be hinting towards more clues about the storyline dancing in the margins of the one-off adventures.
After last season's "Tales From the Citadel," Evil Morty has assumed power over the entire governing body of Ricks. It all happened in a story that seemed to be setting up an episode where a bunch of loosely related plot threads were just floating there. But, now the big antagonist is here and more menacing than ever. That can't mean good things for Rick C-137 and his family.