The MCU has introduced several different ways to travel through the multiverse and its many dimensions. During Phase 4, the volume of the MCU multiverse grew at an incredible rate, presenting various alternate realities filled with different versions of familiar faces and even completely new characters that are not in the main MCU universe. But although the multiverse has taken center stage in the franchise, there are still more questions about its nature than there are answers.
Like superpowers, deities, and witchcraft, the multiverse can be approached by both scientific and magical means. Scientists like Hank Pym and magic users like Doctor Strange and the Scarlet Witch have made important discoveries about the multiverse, but even they don’t have a clear idea of its inner workings. It looks like the multiverse is quickly becoming a big threat, and every time a character starts to realize this, a new multiverse event happens to shake things up.
KVM presented such universes as Earth-616 Avengers, Earth-838 Illuminati and the Raimi universe. It also presents dimensions such as the Soul World, the Ancestral Plane, and Ta-Lo. Although these dimensions are not exactly parallel universes, they are still extraneous realities that cannot be accessed through conventional space travel. Concepts such as intrusions and variants have yet to be fully explained, but if there is one thing certain, it is that there is more than one way to travel to other planes of reality. These are the ones that are represented in the MCU so far.
Time Travel and the Quantum World — “Avengers: The Finale”
The dimension itself, the Quantum Realm is so small that it is almost impossible to even detect it. “Avengers: Finale” showed that the Quantum World also serves as the key to time travel, which not only allows the Avengers to retrieve weapons from the past, but also allows you to expand the timeline of the MCU. Fortunately for the stability of the multiverse, the Avengers avoided changing past events, and TVA ensured that the new timelines would not be able to evolve into unique universes. However, Loki’s escape with the Tesseract proves how dangerous time travel can be. If minimal change means that a completely different person can appear, then time travel can be an ideal tool for creating infinite universes if it falls into the wrong hands.
TVA and the Citadel at the End of Time – Loki
TVA managed to stop the collapse of the Sacred Timeline thanks to the One Who Remains, who protected it — apparently – out of pure generosity. The organization can travel to any point in the timeline using an arsenal of high-tech tools such as TempPads and Time Doors, which seem to combine time travel with teleportation and magic. However, in reality, things may be more complicated than it seemed under the TVA, since different options were allowed to exist only as long as they did not make a certain decision. This means that other parallel universes have always existed and TVA allowed them to remain free as long as they did not threaten their common plans. Somewhere out there, the home universes of variants such as Sylvie Lafeydottir, the Alligator version of Loki and Trog may continue to exist as unique realities.
The TVA itself exists outside of space and time, which means that arriving at their headquarters is considered a multiverse journey. But TVA also has access to other planes of existence: the Void, where all the stripped-down options go to live forever, and the Citadel at the End of Time, where the One Who Remains has guarded the Sacred Time Line for eons. Access to the TVA, the Void and the Citadel at the end of time is possible thanks to the technology of the 31st century of Tom Who Remains, which is developed beyond comprehension. Only the arrival of Kang the Conqueror could give some insight into how the One Who Remains really took control of the multiverse. Given his connection to Reed Richards and Dr. Doom in the comics, it’s possible that this could also be due to the fusion of science and witchcraft.
The connection of all realities – What if…?
Uatu and the Observers inhabit the Nexus of All Realities, a dimension beyond the MCU multiverse where Observers observe every existing universe. It is assumed that this place is unattainable, since it is not an ordinary universe, but an external dimension that binds all universes together. However, a variant of Ultron using the power of Infinity Stones was able to see through reality itself and interact with Uatu.
Only beings with a higher power can sense the Nexus of All Realities, let alone travel to it. Observers can move freely between the Nexus and each universe, but given that they have sworn an oath never to interfere, they rarely leave their home.