As Marvel’s Eternals finally approaches its November release, we’re slowly starting to understand how epic Chloe Zhao‘s film will be. The recent trailer finally revealed much-awaited plot details, including hints at what the Eternals are up against — and who is standing in their way.

As Eternals leader Ajak (Salma Hayek) explains, the sudden returns of half the universe’s population in Avengers: Endgame caused a powerful surge of energy, triggering the "emergence." While she doesn’t exactly go into details about what that means, it’s serious enough to warrant the Eternals finally regrouping after decades apart. And after 7,000 years of staying out of cataclysmic events, the Emergence requires them to intervene.

Current speculation says the Emergence probably involves the release of the Eternals’ sworn enemies and dangerous counterparts, the Deviants. In the comics, the genetically unstable Deviants raged a millennia-long war against the immortals. One of our biggest hints came in the form of plastic, when Kro was unveiled as part of the movie’s upcoming toy collection. We also get a few quick glimpses at Kro, and a hint of what seems to be a pretty intense villain monologue. So as part of the ongoing quest to crack exactly what Eternals is trying to keep hidden, we’ve done a deep dive into Kro’s comic book history.

Here’s what we already know about the Deviant villain.

Who is Kro?

Kro was born to the race of Deviants, an evolutionary offshoot of humanity created by the Celestials but cursed with an unstable genetic code. As the name implies, no two Deviants are alike. The flaw of their design is that each member of the race has unique characteristics. Kro won the genetic lottery — whatever set him apart from the others, has allowed him to live out a prolonged existence alongside other immortal Eternals. In some ways, Kro is closer to the Eternals than his own kind. The Deviant is over 20,000 years old and over the course of his long existence has taken many forms.

As one of the first Deviants created, Kro occasionally takes the lead of the race as a whole. In the comics, he’s known as a military leader and warlord, often involved in attacks against humanity, the Avengers, and the Eternals. However, Kro tends to do so under alternate identities, as he keeps his immortality hidden from the rest of his kind. Fearing their response to his unique immortality, he pretends to be a long line of fathers and sons — which isn’t too difficult, given his shapeshifting abilities.

When not focusing all his energy on hiding secrets from his race, Kro has a thing for wreaking havoc. The Deviants believe they should inherit the earth and frequently put together plans to make the planet their own. Individually, Kro’s interactions with humanity often involved chaos. As mentioned in our breakdown of the Eternals characters, many members of the immortal race are mistaken for Gods and equated to figures from folklore and history. Kro is no exception — an immortal figure himself, Kro has been noticed throughout time and many humans think of him as a devil figure. Kro has been mistaken for various rulers of the underworld, including Pluto and Satan. In the comics, he embraces this reputation and often takes on devilish forms.

What Are Kro’s Superpowers?

As mentioned, Kro is immortal, having lived beyond 20,000 years. He’s proven immune to aging and dying, but also doesn’t take harm like other members of his race. Kro has resistance to harm and, when injured, his body can repair itself at an accelerated rate. It’s not unlike the Eternals’ ability to self-heal, another way in which Kro is close to them. Like other Deviants, Kro is superhumanly strong. Over time, he’s also become a master military strategist and commander.

Kro’s shapeshifting abilities have allowed him to stay hidden amongst his own kind. He’s able to change his face to create new appearances and identities as time passes, simulating aging by altering his features.

What Does Kro’s Relationship With Thena Mean for The Eternals?

Marvel has been touting Eternals as a love story and what little we know seems to indicate a love triangle between Ikaris, Sersi, and her human lover. That’s pretty ripe from drama all on its own, but they aren’t the only immortals with relationship problems. In the comics, Kro has a heated romantic background with one of the group’s fiercest warriors, Thena (Angelina Jolie).

Yes, even villains have hearts. Back in fifth century Babylon, Kro met and fell in love with Thena. A star-crossed romance, their relationship would not have been well received by either race — so they did their best to keep it secret. In the short term, it didn’t matter too much. The romance ended badly and they spent many centuries apart. Eventually, the pair reconnected in the 60s, resulting in Thena becoming pregnant with twins, the first Eternal-Deviant hybrids. Their romance continued down an on-again/off-again road, with various instances of Thena saving Kro from destruction via her fellow Eternals. At one point, she even releases him from a cell, allowing him to narrowly escape death.

But what does this mean for the MCU iteration of these characters? Kro and Thena have all the makings of a very twisted love story, and the trailer indicates the movie will put that to use. We briefly see Kro trap Thena in his creepy tendrils while telling her that she can’t protect "any of them." Whether this is in reference to the Eternals or humanity is unclear, but it’s safe to assume Kro is willing to harm both races. Thena’s eyes glow as Kro caresses her face, but we don’t get much indication of the state of their relationship. It seems telling that they’re alone and exchanging words — indicating that Eternals will reference their entangled history. In the comics, the relationship has been enough motivation to make the pair work together — but if Kro is threatening Thena’s family, things may not be that simple.

Whatever Kro is up to, the Deviant has the potential to be one of the MCU’s more interesting villains. Between his creepy shapeshifting abilities, immortality, and complicated past with one of the heroes, Kro may prove even more complex than he appears.