The Quantum Realm is highly-expected to factor in the story of Avengers: Endgame, which will help the Avengers defeat Thanos once and for all, and there are already plenty of clues in the movie's marketing so far.

Introduced in 2015's Ant-Man & The Wasp, which offered the best look at the largely unexplored realm when Hank traveled through the Quantum Tunnel to save the original Wasp, Janet van Dyne, who had been trapped there for decades.

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The Quantum Realm's involvement in Avengers: Endgame is linked with the popular theory that the Avengers: Infinity War. Here are all the clues suggesting that it will be pivotal in the heroes' mission.

The Avengers' Wrist Devices

The Avengers Battle of New York

The mysterious wrist devices were first spotted on the The Avengers. The paraphernalia and its uses quickly roused questions from fans. In the images, the heroes are wearing the device at the back of their left wrists, and based on its green face, more details are expected to be added during post-production.

The same wrist piece was featured in a couple pieces of Endgame's tie-in merchandise, such as a brand new Avengers: Endgame's second trailer. During a split-second shot, Hawkeye can be seen wearing the same device when he and Black Widow are aboard what appears to be the Benatar. Based on Nat's grown hair, time has ed since the events of Infinity War at this point.

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So how does the device link up to the Quantum Realm? It goes back to theories about how the alternate dimension will allow the heroes to travel back in time and this accessory might help make it happen. It could serve as a guiding equipment for the Avengers as they travel through time and space, ensuring that they will land on the specific setting they want to revisit. Another possibility is that it enables them to navigate previous events without effectively rewriting history and rendering everything that the MCU has built up to this point insignificant.

Ant-Man's Quantum Tunnel Van

Scott Lang on camera in Avengers Endgame

During the first Avengers: Endgame trailer, the same van can be spotted with Scott outside the Avengers HQ as he asks the heroes to let him in.

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It's still unclear how Avengers: Endgame's Super Bowl spot revealed that he will the remaining heroes left alive, effectively providing the Avengers with access to the Quantum Realm. This makes it easier for them to dive into the subatomic dimension once they've discovered its capabilities that might allow them to travel back in time.

Page 2 of 2: Hank Pym's Building & The Avengers' White Suits

Hank Pym in Ant-Man and the Wasp Cropped

Hank Pym's Building

Luis' van isn't the only thing from Ant-Man & the Wasp to make an appearance in Avengers: Endgame. The second Endgame trailer also appeared to reveal Scott with Hank's shrinking building, and unlike the van, this one isn't as easy to spot. Scott appears to be dragging Pym's lab as he walks through a deserted street staring at a post covered with missing person flyers. Previously leaked set photos show Ant-Man pulling a prop that could double as the building. And while it noticeably has a different handle from Pym's building in Ant-Man & the Wasp, Marvel Studios can easily add/change details using CGI during post-production.

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If the Avengers already have the van with the miniature Quantum Tunnel providing entry to the Quantum Realm, then why still the need for the original-sized one in the lab? There are a couple of reasons; one is that it may have something to do with the other apparatuses in Pym's workspace that will help better operate the tunnel. In the post-credit scene for Ant-Man & the Wasp, Scott didn't care much about where he's landing as long as he won't be sucked in a Time Vortex and he's able to gather the Quantum Particles. But earlier, Hank and Hope had to use an elaborate navigating system in the building to pinpoint where exactly Janet was in the Quantum Realm. As we've seen in set photos, the Avengers may be re-exploring specific events, like the Battle of New York, in Endgame. Configuring the navigating instrument with the wrist devices we've seen them sporting could ensure that they're exiting the right timeline. It's also possible that they'll need the bigger tunnel to transport multiple people, or go deeper into the subatomic dimension.

The Team's New Suit

An image of the Avengers walking together in the MCU

Perhaps the biggest and earliest indication that the surviving heroes will enter the Quantum Realm is the reveal of their new matching red and white suits, dubbed the "concept art showed Iron Man, Captain America, Thor, Hawkeye, Ant-Man, Rocket, Nebula, Hulk, and Black Widow in the futuristic gear.

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It wasn't until Avengers: Endgame's second trailer, however, that fans got official confirmation that these suits will indeed appear in the film - with a final shot of the heroes walking down the Avengers HQ hangar wearing the matching costumes. The gear is mainly regarded as the Avengers' uniform for the Quantum Realm since its design is similar to the the armor Hank wore when he traveled to the Quantum Realm himself. As Janet warned in Ant-Man & the Wasp, certain parts of the subatomic world is dangerous to the human mind, establishing that one needs a proper set of gear before entering. Despite being fully-decked out, Hank still experienced phasing like Ghost upon his arrival, which only stopped when Janet stabilized him. We expect Tony Stark, with the assist from fellow mechanics like Nebula, Rocket, and maybe even Shuri, made some modifications to Hank's original design to make it better-suited for the mission that lies ahead.

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Marvel Studios president Kevin Feige has repeatedly reiterated that the MCU still has a lot to do with the Quantium Realm. ittedly, not much is known about it so it's difficult to gauge how it can factor in Avengers: Endgame. Regardless, fans can expect to see more of it past Phase 3.

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