Time travel! As Tony Stark warned in Avengers: Endgame, when you mess with time, it tends to mess back. Thanks to Sylvie’s actions at the end of the Season 1 finale of Loki, the heroes of the MCU are about to find out what happens when you come face-to-face with the Master of Time as Jonathan Majors‘ Kang the Conqueror is set to wreak havoc across the Multiverse. Rumors have Kang wiping the floor with the Avengers in Avengers: The Kang Dynasty before facing off against a multiversal team of heroes in Avengers: Secret Wars. While everyone ultimately expects a big win for the good guys, a crazy theory puts forth the idea that fans may have already seen the aftermath of the big battle against Kang!
The theory comes courtesy of Heavy Spoilers and it packs a pretty meta punch. Rumors of the plot of Avengers: The Kang Dynasty have the Avengers teaming with a version of He Who Remains, a Nathaniel Richards Variant first met in Loki. This Variant, who hasn’t become He Who Remains yet, goes by Nathaniel and eventually helps put together a multiversal team of heroes that take on Kang in Avengers: Secret Wars. According to the theory, once Kang is defeated, Nathaniel will go on to become He Who Remains and create the TVA in order to oversee the Sacred Timeline, just as seen in Season 1 of Loki!
If that theory were to play out in Avengers: Secret Wars, it would mean that the aftermath of that film will already have been shared with fans years in advance of it occurring on screen! This would mean that the story He Who Remains tells Loki and Sylvie about the peace between realities erupting into an all-out war was only in the past from his perspective and that he was actually describing the events of Avengers: Secret Wars to fans years before they would ever see the film. To quote Marty McFly, “this is heavy.”
Source: Heavy Spoilers