WARNING: The following article contains spoilers for Captain Marvel, which opens March 8 nationwide.

Annette Bening's secretive role in Captain Marvel has been the subject of intense speculation since her casting was announced in May 2018, when early reports pointing to the four-time Oscar nominee playing Carol Danvers' mother. Those rumors evolved in another direction, until the actor finally confirmed her character Thursday during an appearance on The Late Show with Stephen Colbert: the Kree Supreme Intelligence. But who, or what, is that?

RELATED: Captain Marvel Cast Honors Goose for #LoveYourPetDay

Bening described the character to the talk-show host as "a godlike entity, the leader of the Kree people, the artificial intelligence which consists of the greatest intellects of the Kree people for the last million years." That's it in a nutshell. Although the film clip that followed, depicting Brie Larson's Danvers conversing with the Supreme Intelligence, revealed that Bening isn't the giant, green floating head familiar to Marvel Comics readers.

If you don't know who, or what that, the Supreme Intelligence is, don't worry. We'll explain.

Often referred to a the Supremor, the Supreme Intelligence was introduced in 1967 by Stan Lee and Jack Kirby in Fantastic Four #65. Just as Bening described, it was depicted as an authority figure for the alien Kree, and was later revealed to be a machine of sorts, built to house and preserve the intellects of the civilization's greatest minds. But although it was created to serve the Kree Empire, it gradually became its ruler, as many worshiped the Supremor in a religious manner.

The Supremor generally acts to further the development of the Kree, which is why it created (and later manipulated) Mar-Vell, the original Captain Marvel of the comics, and attempted to destroy humanity. However, Earth's mightiest heroes put an end to those plans, and have even sought to destroy the Supreme Intelligence itself. But the Kree machine repeatedly proved itself to be far more powerful and forward-thinking than previously realized.

In the Captain Marvel clip, the Supreme Intelligence doesn't look like her comic book counterpart; she's far more human and expressive. However, beyond a humanoid figure being more relatable on film than a giant floating head with tentacles for hair, the Supremor's appearance can be explained by its vast array of powers. Along with its superior intellect, the Supremor possesses an array of psionic powers: telekinesis, telepathy, precognition and more. As if that weren't enough, it can also control and reshape matter. Despite all that, the Supreme Intelligence is virtually immobile, and relies upon a housing structure to survive.

RELATED: Captain Marvel: First Reactions Praise 'Surprising,' 'Badass' Film

There's still some amount of mystery surrounding Bening's role. Jude Law has stated that each member of Starforce has a different relationship with the Supreme Intelligence. However, given that several of those members become villains later in the timeline, and that the Supremor is a villainous character in the comics, it's not unreasonable to think the major antagonist in Captain Marvel may not be the Skrulls, but instead the Supreme Intelligence.

Directed by Anna Boden and Ryan Fleck, Captain Marvel stars Brie Larson as Carol Danvers, Samuel L. Jackson as Nick Fury, Jude Law as the commander of Starforce, Clark Gregg as Phil Coulson, Lee Pace as Ronan the Accuser, Djimon Hounsou as Korath the Pursuer, Gemma Chan as Minn-Erva, Ben Mendelsohn as Talos, Lashana Lynch as Maria Rambeau, Algenis Perez Soto as Att-Lass, McKenna Grace as a young Carol Danvers and Annette Bening as the Supreme Intelligence. The film arrives in theaters March 8.