The MCU multiverse may sound simple at first but really, it’s confusing at best. We’re dealing with different universes, a multiversal war, and incursions, and it makes you wonder how any of this is even possible. Fortunately, someone has drawn a handy simple guide to the history of Marvel’s multiverse, based on the given explanations in Loki.
This handy guide was drawn by Reddit user u/gimboarretino, and it tries to demonstrate how the MCU multiverse works and what defines “the sacred timeline.” It also tries to explain how He Who Remains’ death in Loki triggered Nexus events and how different variants of Kang are now meeting each other.
This image may be still confusing for those who didn’t get it. But at the same time, it does make some things clear, especially when it comes to understanding what the sacred timeline is. Due to a lack of any explanation, people assumed that the sacred timeline is just a single universe when in reality it’s just an isolated timeline that doesn’t branch out into other universes.
This might explain why America Chavez was able to jump across multiverses. Or how Tobey McGuire and Andrew Garfield are still alive. Because their universes are not part of the isolated timeline.
If this diagram is confusing, essentially, the point of the sacred timeline is to follow a strict script to prevent the birth of evil Kang variants and spark another multiversal war. Meanwhile, there are other multiverses out there that are pretty much out of reach from the main MCU timeline and are just left alone.
The role of the TVA is to cut off Nexus events from the sacred timeline that could spark another war. At the same time, branches from the timeline were allowed to exist as long as certain conditions aren’t met. This may explain why Classic Loki (played by Richard E. Grant) was taken by the TVA after he decided to see his brother again, because his desire for a brotherly reunion may pave the way for a multiverse incursion.
In the end, understanding the multiverse saga may be confusing, mostly because the ground rules haven’t been fully outlined just yet. We’ve only been introduced to the concept in Loki Season one, Doctor Strange and the Multiverse of Madness, and Ant-Man and the Wasp: Quantumania. So perhaps more details on how the multiverse works would be revealed once more MCU films are released.