Way back in 2016, it’s fair to say that the general public didn’t know much about Doctor Strange. Maybe people knew that magic is his thing; perhaps they would recognize his cape and general appearance. Things are a bit different now that Strange has headlined his own Marvel film, lent a hand to two giant AVENGERS films, and stepped into a major role in SPIDER-MAN: NO WAY HOME.

People are a lot more familiar with the character, and anticipation is high for his second solo movie, DOCTOR STRANGE IN THE MULTIVERSE OF MADNESS. (Maybe put air quotes around "solo" there since quite a few other familiar characters will appear.)

But much of Doctor Strange's history isn't yet common knowledge, especially with respect to his stable of villains. And even with IN THE MULTIVERSE OF MADNESS set to debut in just over a month, we don't know who the movie's true big bad is. So let's look at Strange's history and line up some clues to see who might bedevil Marvel's big-time sorcerer in his new movie.

Chiwetel Ejiofor played Mordo in the first DOCTOR STRANGE, in which he's a student alongside Strange. Eventually, he came to believe that Strange and his mentor the Ancient One were abusing their power, and he became determined to eliminate sorcerers from the world. He appears in MULTIVERSE OF MADNESS, but it’s unclear if he’s the main villain or just one of several baddies the film has to offer. For those who don’t remember the character, he’s much like Strange himself: a human practitioner of the magical arts. But also: evil. (Or evil-ish.)

Known as “The Archdemon of Chaos”, Chthon is a figure of great power and horror in the Marvel Universe. For instance, in comics, he’s the guy who gave Wanda Maximoff her powers, which can be quite scary if she chooses. Furthermore, he also gave the universe its vampires and werewolves. The streaming series "WandaVision" ended with the suggestion that Wanda had taken refuge on the mountain where Chthon is imprisoned, leading to the supposition that he'll be a player in DOCTOR STRANGE 2.

This tentacled, single-eyed giant is one of "the old ones," and a force of chaos that rules hundreds of worlds. In comic book stories, Strange has kept the big starfish in check, usually at great cost to himself. Many Doctor Strange villains worship Shuma-Gorath, to put its supremacy into perspective. Trailers suggest that Shuma-Gorath will appear in THE MULTIVERSE OF MADNESS, but with a different name: Gargantos. (The character's name change is likely not due to any sorcery, but to the simple complication of rights issues.)

Mephisto is one of Marvel’s more recognizable villains, if only because he looks like the Devil. Some think of him as the Marvel Universe’s version of Satan, but that’s kind of an oversimplification. He is a demon, however, one Strange would do well to avoid if possible (spoiler alert: it’s usually not possible). Mephisto's involvement in STRANGE 2 has been theorized for several years, especially since his story has often intersects with both Strange and Scarlet Witch. While one figure in the latest trailer could be him, it is more likely to be…

Nightmare is a lord of fear who rules over dreams and can trap characters in nightmares, allowing him to feed on their terror. He was once planned for the original DOCTOR STRANGE movie by director Scott Derrickson, who suggested that Nightmare would be a key player in the sequel. When Derrickson moved on from STRANGE 2 we guessed that Nightmare might have gone with him — but trailers show that the sorcerer is plagued by bad dreams, and a couple of shots suggest that one Multiverse variant of Strange is revealed to be Nightmare.

The animated streaming series "What If…?" introduced the evil Strange Supreme, who is a product of Strange's grief following a massive personal loss. The evil Strange in the latest MULTIVERSE OF MADNESS trailer looks similar to Strange Supreme, but there's no question that, in the aftermath of NO WAY HOME, Strange is battling his own choices and, in effect, himself. So an evil version of Doctor Strange is an appropriate manifestation of his own core problem.

DOCTOR STRANGE IN THE MULTIVERSE OF MADNESS opens on May 6.

All images courtesy of Marvel Comics and Marvel Studios.