Warning: SPOILERS for Guardians of the Galaxy Vol. 2 are ahead!
Even though Guardians of the Galaxy Vol. 2 was one of the more self-contained Marvel Cinematic Universe movies, director and writer James Gunn squeezed in a remarkable number of Marvel Easter eggs. A smaller one that passed by in a blink-and-you'll-miss-it moment was when Rocket, Yondu and Kraglin were were traveling at top speed to reach the Guardians on Ego, and one of the worlds they passed by had two rock-like humanoids fighting each other on it. While those aliens may have been instantly recognizable to longtime Marvel fans, Gunn has identified those brutes as Kronans and revealed that we'll be seeing their kind again, saying:
James Gunn officially naming those Guardians of the Galaxy Vol. 2 aliens as Kronans during an interview with IGN is appreciated, but noting that we'll be seeing them again at some point confirms that these beings aren't just sly winks to the comic book readers in the audience. They're a recurring element in this cinematic world. For those unfamiliar with the comics, Kronans have been part of the Marvel mythology since 1962's Journey into Mystery #83, the same issue that introduced Thor. As you can tell by their build (which is reminiscent of The Thing from the Fantastic Four), they are extremely strong, but they are also are highly advanced, with one of their impressive technological achievements being a machine that can create convincing illusions.
It's important to note that Guardians of the Galaxy Vol. 2 wasn't the first time a Kronan appeared in the MCU. In 2013's Thor: The Dark World, Thor battled a Kronan on Vanaheim, the home of Hogun, one of the Warriors Three. While the unnamed Kronan looked formidable and menacing, the God of Thunder instantly destroyed it with one blow from Mjolnir. Given that the comic book Kronans debuted at the same time as Marvel's Thor, it was fitting that one of them was thrown into his movie. And that won't be the only time Chris Hemsworth's iteration of the Odinson encounters this species.
While James Gunn played coy on when the Kronans will appear in the MCU again, it's already been confirmed that at least one of them will appear later this year in Thor: Ragnarok. Although Thor's main objective in his third solo movie will be trying to stop Cate Blanchett's Hela from destroying Asgard, the story is also adapting elements of the Planet Hulk storyline by stranding the God of Thunder on the planet Sakaar, which is ruled over by Jeff Goldblum's Grandmaster. The main event of this detour will be Thor going head-to-head with Hulk in the gladiator ring, but one of the other aliens Thor will encounter on that world is Korg, arguably the most famous Kronan from the comics. Performed by Thor: Ragnarok's director Taika Waititi through motion-capture, the MCU's Korg is one of the few characters who will befriend Thor on Sakaar, and he's described as being funny and having a "light soul." Whether or not other Kronans will appear in Thor: Ragnarok remains to be seen, as does if they'll show up in another cosmic-centric MCU tale, like Avengers: Infinity War or Guardians of the Galaxy Vol. 3.
The Kronans will score their longest amount of screen time yet when Korg debuts in Thor: Ragnarok on November 3.