What Is Marvel's Quantum Realm? Here's What We Know

The newest Marvel film, "Ant-Man and the Wasp: Quantumania," follows the titular heroes as they head into one of Marvel's most mysterious areas: the Quantum Realm. There, Scott Lang (Paul Rudd), Hope van Dyne (Evangeline Lilly), and company meet an alternate timeline variant of Kang the Conqueror (Jonathan Majors), first introduced as He Who Remains at the end of "Loki" season one. Kang is set to be the overarching villain of Marvel's Phase 5, culminating in a Phase 6 Avengers movie titled "The Kang Dynasty." The Quantum Realm played a role in 2015's "Ant-Man" and 2018's "Ant-Man and the Wasp" (plus it helped the Avengers figure out how to time travel in 2019's "Avengers: Endgame"). But if you're still a little confused, we're breaking down what the Quantum Realm is, what we've learned from its previous appearances on screen, and what it all means for "Quantumania."

In the MCU, the Quantum Realm is a separate dimension. The main ways of accessing it (that we know of so far) are via Pym Particles (which power Ant-Man's suit) or via a Quantum Tunnel. Pre-"Quantumania," it's mostly been depicted as a mystical, incorporeal place, but in the new movie, it resembles something more akin to an alien planet where many people live.

In addition to the Ant-Man movies, it also played a role in the "Agents of S.H.I.E.L.D." TV show, which ended in 2020. In that series, characters used it not just to travel through time, but also to access other dimensions in the multiverse. However, it's not quite clear if the events of that show are considered canonical for the rest of the MCU.

Hank Pym (Michael Douglas) first introduces the idea of the Quantum Realm in the first Ant-Man film. He warns Scott that the suit he's made, which can make him small using Pym particles, is not perfect. If Scott overrides the suit's regulator, he could be sent to the Quantum Realm, the same fate that Janet Van Dyne (Michelle Pfeiffer) suffered in 1987. Janet, he says, is still trapped there. Scott does momentarily access the Quantum Realm during the film but is able to break out of it. They also send Darren Cross, aka Yellowjacket (Cory Stoll) there at the end of the movie.

"Ant-Man and the Wasp" builds upon the Quantum Realm lore. Hank and Hope work on freeing Janet from the Quantum Realm, while Scott realizes that his trip to the Realm in the first movie has left him and Janet quantumly entangled. The trio work on a Quantum Tunnel they can use to rescue Janet. One of their adversaries is Ava Starr, aka Ghost, who's quantumly unstable and is trying to access quantum energy to fix herself (the character will return in the "Thunderbolts" movie). She also has the power to phase through objects because of her quantum powers. At the end of the movie, Scott, Hope, Hank, and Janet work on harvesting energy to help Ava stabilize, but Thanos's snap happens, and Scott gets trapped in the Quantum Realm as his companions disappear.

In "Avengers: Endgame," Scott is finally freed from the Quantum Realm five years later. For him, it was only five hours. The Avengers are able to harness the power of the Quantum Realm to travel back in time and get new Infinity Stones that help them beat Thanos once and for all.

Interestingly, the Quantum Realm also appeared in 2016's "Doctor Strange" when the Ancient One (Tilda Swinton) used magic to send Dr. Stephen Strange (Benedict Cumberbatch) through it during his training to become a sorcerer. Presumably, he and other sorcerers could still use magic to access it.

"Ant-Man and the Wasp: Quantumania," set in this post-snap world, sees the series's heroes' — plus Scott's daughter Cassie Lang (Kathryn Newton) — journey into the Quantum Realm.

In "Quantumania," the Ant-Family is sucked into the Quantum Realm. We learn that Janet never told her family what her 30 years in the Quantum Realm were really like. It's almost like an alien planet, full of different types of quantum people. Some of them have powers, like Quaz (William Jackson Harper), who can read people's minds. There are people made of goo, people whose heads are laser cannons, and people who seem pretty much identical to humans, with minor differences. There's also a host of unique animals.

When Janet was trapped in the realm, she met Kang, who claimed he was a marooned scientist from the future like her. She helps him repair his ship, and he promises to bring her home. But when the ship is fixed, she finds out he's a bad guy, and she joins up with other members of the Realm to fight back until she escapes the Realm.

Janet tells her family that the Quantum Realm is wider than what we see in the movie, but in the part we do see, there's the freedom-fighting refugees fighting for survival, and there's the luxurious empire created and maintained by Kang. The empire has a definite Star Wars vibes, only more brightly colored and a little kookier.

The Quantum Realm, it seems in the movie, exists at both a nexus of time and the multiverse. Kang tells Janet and Scott that it would be possible for him to exit it at any point in time, and at anywhere in the multiverse. It's not clear what role the Quantum Realm will have in future movies, but as we saw in "Endgame" and "Loki," time travel and the multiverse will both play major roles in the MCU going forward.

"Ant-Man and the Wasp: Quantumania" is in theaters now.