In the final trailer for Marvel's Eternals, Sersi (Gemma Chan) says that she and the other Eternals were instructed not to get directly involved with human wars and atrocities unless Deviants were directly involved. This is an easy explanation for why these massively powerful beings didn't stop Thanos (Josh Brolin) from decimating half of the universe's population, or any of the lesser MCU villains that preceded him. However, for those unfamiliar with Marvel's comic books, Sersi's response raises as many questions as it answers.
The Deviants seen in Eternals differ physically from those in the comics, but they serve a similar role as foils to the titular superheroes. It remains to be seen how much of the two groups' intertwined backgrounds will translate to the screen, but here's a breakdown of what we know about the species so far.
Who Are the Deviants - and What's Their Connection to the Eternals?
The Deviants first appeared in Eternals #1 (July 1976). They were created by the Celestials, the extraterrestrial beings introduced to film audiences by the Collector (Benicio Del Toro) and further explained by Ego (Kurt Russell), the power-hungry father of Peter Quill (Chris Pratt) and a Celestial himself. The species was created when the Celestials obtained a group of Homo erectus known as the Wanderers. One Celestial, Ziran the Tester, caused a mutation in the proto-humans that created the Deviants, also known as Homo descendus. The Deviants had "destabilized DNA" that led to mutations that manifested in both physical differences and unusual powers.
Deviants that were too strange -- or too normal -- were often exiled or killed. Some of the more non-human Deviants were called Mutates; if and when they interacted with humans, they prompted fantasy and folklore about trolls, ogres, and monsters. In addition to physical mutations, Deviants generally had at least one superhuman ability, such as enhanced strength or longevity. Things like love and friendship were uncommon in Deviant society, as they were deeply hostile, even to each other.
The Eternals (Homo immortalis) also descended from humans altered by Celestial experimentation. The Deviants preceded the Eternals, but the Eternals were advanced in every way. They were given the directive to protect Celestials and the Earth, including from the Deviants, who multiplied much faster and attempted to subjugate humans. Deviants and Eternals have long considered each other nemeses, as shown in the final Eternals trailer.
Their Physical Appearance in Comics vs. the MCU
The comics' Deviants are mostly humanoid but still distinctly other. Some are abnormally muscular or tall; many of them have unusually-colored skin or skin with non-human textures, like spikes or furrows. As mentioned, some of them have characteristics that were later attributed to fantasy creatures like trolls, including odd proportions, jutting jaws, sunken eyes, and more, and they're conventionally unattractive, especially in contrast to the Eternals.
The Deviants seen in the Eternals trailer differ from their comics counterparts in several ways, if the short scene featuring Thena (Angelina Jolie) and main Deviant villain Kro is any indication. He's significantly taller than Thena and, by extension, most normal humans and humanoid creatures. Instead of pink skin like his original comics counterpart, he seems to be blue-green with gold markings; this suggests that other Deviants' colors will also stray from the bright colors found in earlier comics. He has long, almost vinelike extra limbs extending from his back, four eyes, and goatlike legs. His body looks more like it's made of muscles than skin, and at least some of him seems to be metallic. This design is much more like modern sci-fi than the classic B-movie alien look the original Deviants had.
Deviants' Powers and Weaknesses
Each Deviant has their own individual combination of abilities, thanks to the species' rapid mutation rate. Kro is functionally immortal, meaning he can be killed by attacks but not by age or disease, and can shapeshift with limits. Brother Tode, the large-headed leader of the comics' Deviant Empire, heals quickly, claims to have "particularly advanced perceptions" and is strong enough to lift his own weight. Ancient Deviant scientist Taras Vol was telepathic; another Deviant named Tutinax was abnormally strong and could create illusions; Ereshkigal, a Deviant who played at being the Mesopotamian goddess of the same name, was long-lived and able to fly. Strength and longevity are common traits, though they aren't universally held.
It remains to be seen how similar the MCU's Deviants will be to their comics counterpart, but there are a lot of intriguing characteristics to pick and choose from.
See the Deviants in action when Eternals is released in theaters on Nov. 5.