The Marvel Cinematic Universe launched a new overarching storyline when Phase Four kicked off “The Multiverse Saga.” Fans of Marvel Comics have explored the multiverse a few different times over the years in events like Secret Wars and Spider-Verse. However, there are a few Marvel heroes who were the first to explore the multiverse in the comics.

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Powerful beings like The Watcher made it their business to observe the multiverse in titles like What If…? which was also adapted to the MCU. Brilliant scientists like Reed Richards discovered alternate dimensions while mystical heroes like Captain Britain were put in charge of policing the larger omniverse of alternate and parallel realities and dimensions.

Avengers Visited The Squadron Supreme’s Earth

The Avengers appearing as ghostly spectres on a dying world

One of the very first examples of modern Marvel heroes traveling to another reality in the multiverse occurred way back in 1971’s Avengers #85 by Roy Thomas and John Buscema. The Avengers previously visited Arkon’s other-dimensional world but didn’t return to their proper Earth.

Instead, they arrived on an alternate Earth protected by a team of heroes known as the Squadron Supreme. This was largely considered to be the introduction of Marvel’s multiverse as well as the Squadron Supreme, pastiches of DC’s Justice League. The Squadron Supreme would travel across the multiverse themselves when they were briefly exiled in the 616 reality.

Mr. Fantastic Discovered Other Dimensions

Reed Richards as Mr. Fantastic

While he's sometimes a Marvel leader who can't be trusted, the Fantastic Four's head is both a scientist and an explorer. Reed Richards is one of the Marvel universe’s smartest heroes, and he has used his inventiveness to create new ways to explore other dimensions and realities.

Reed Richards was one of the first who discovered the existence of the anti-matter dimension known as the Negative Zone. While it wasn’t technically an alternate reality in the multiverse, it serves as one of the first times Marvel heroes left their own dimension. He would later create the Bridge to confer with the Interdimensional Council of Reeds who each mastered multiversal travel.

Thor Traveled Across Numerous Realms

Thor with the Odinforce

Much like his father Odin, Thor had many adventures on Midgard across the centuries. However, by his very nature as an Asgardian, Thor traveled across a number of different realms long before he ever met the Avengers. Asgard lived in a constant cycle of rebirth caused by Ragnarok.

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This meant there were multiple versions of Thor and Asgard that came into being over the years and the multiverse. The modern version of Thor has lived for centuries and traveled across the multiverse as needed with the power of Mjolnir, predating many of Marvel's scientific discoveries of other realities.

Ant-Man First Explored The Microverse

Ant-Man crawling through tunnels with ants in the comics

Hank Pym discovered a size-changing particle that allowed him to shrink down as the founding Avenger known as Ant-Man. However, he soon discovered he could further manipulate the Pym Particles to allow him to shrink small enough to access an entirely different universe that would become known as the Microverse.

Other characters like Doctor Doom accidentally discovered the Microverse, though Ant-Man was the first modern hero to use his technology to reach and explore the "Quantum Realm." He helped the Fantastic Four access it before he further mapped it out over the years. Other heroes who used the Ant-Man identity have used the Pym Particles to explore the Microverse as well.

Blue Marvel Discovered The Neutral Zone

Blue Marvel flying through space in the comics

Dr. Adam Brashear is an incredibly brilliant scientist who is also one of Marvel's most powerful heroes. Exposure to anti-matter energy from another reality turned him into a living reactor. He became the masked hero known as the Blue Marvel, though he retired from active duty in the '60s.

However, Blue Marvel continued his research and discovered an alternate reality he initially called the Neutral Zone. Blue Marvel later described it as Exo-Space after he explored it further. The Neutral Zone/Exo-Space exists between the various realities of the multiverse and serves as a buffer zone to whatever exists outside of the Marvel multiverse.

Doctor Strange Used His Magic To Explore The Multiverse

Doctor Strange casting an elaborate spell with Clea in the background

Stephen Strange was a gifted surgeon when he lost the use of his hands in an accident. His injuries inspired him to seek out new ways to heal himself, which ultimately uncovered a new path. He became a Master of the Mystic Arts and the Sorcerer Supreme.

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Doctor Strange became the mystical defender of Earth in the 616 reality. He has many counterparts across the multiverse who fulfill the same function as well. Doctor Strange has used his mystical abilities to travel to other dimensions and realities quite a few times. He has continually faced multiversal threats like Shuma-Gorath and Dormammu from the Dread Dimension.

Captain Britain Is An Omniversal Protector

Captain Britain holding the Union Jack ready to fight

Grad student Brian Braddock gained the powerful costume of Captain Britain after choosing the Amulet of Right from Merlyn and Roma. However, he had no idea that his role as the patriotic hero would take him outside of his own reality as a member of the Captain Britain Corps.

The celestial being known as Roma created the Captain Britain Corps to protect the interests of Britain in every reality. This sent Captain Britain on a number of missions across the omniverse, where he met other heroic versions of himself. He even went on a “Cross-Time Caper” with Excalibur that saw the team jump uncontrollably to a number of different realities and time periods.

The Watcher’s Mission Is To Observe The Marvel Multiverse

Uatu the Watcher holds his heart and looks down on the moon as Earth sits behind him

Uatu the Watcher is a powerful being from a cosmic race tasked with observing realities but sworn to never interfere with the development of sentient species. He has played witness to a number of important Marvel events both in the 616 reality and beyond.

As the narrator and sometimes star of Marvel’s multiversal What If…? comic series, Uatu the Watcher told stories of other realities in the multiverse. Small and large events played out differently than in the 616 reality. While he usually withheld his oath of non-interference, Uatu has occasionally gathered other heroes from other realities together to stop threats to the multiverse.

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