Odds are pretty good that if you’re reading this, then you’re probably aware of a little movie coming out later this week called Deadpool & Wolverine. You may have also seen a character pop up in the trailers played by a very bald Emma Corrin. If you saw those trailers and were utterly baffled as to what character that is from the comics, then you’ve come to the right place. That character is Cassandra Nova, and she is one of the most terrifying villains the X-Men have ever encountered.
First things first, you should absolutely read Grant Morrison’s run on New X-Men (2001-04). It’s one of the best X-Men runs of all time. If you don’t want to invest the time needed to read all forty-three issues of the run (forty-four if you include the annual), then I would suggest at least reading the issues with Frank Quitely providing the pencils (a mere ten issues). That includes the first three issues of the run that set the tone for Morrison’s entire duration on the book, and it introduces the world to Cassandra Nova.
New X-Men #114-116 by Morrison and Quitely comprise the “E is for Extinction” storyline that sees the X-Men go from the more traditional superhero team that they had become in the ‘90s to a kind of covert ops strike team dealing with threats to mutantkind. They ditched the colorful spandex costumes in favor of leather outfits (in perfect harmony with the suits in the X-Men feature film that had come out the previous year), and the subject matter of these first few issues became both headier and heavier. Cassandra Nova is introduced in this story as seemingly hiking in Ecuador with a member of the Trask family (Bolivar Trask being the scientist responsible for creating the mutant hunting Sentinel robots). She’s an unassuming figure. She’s short, bald, and appearing to be in her sixties while wearing a beige safari outfit that you would expect a Victorian era British colonizer to be wearing. She’s also filling Trask’s head with visions of Neanderthals being massacred by their modern human successors. The point is obvious: mutants will eventually do the same to humans. It’s much easier to generate genocidal intentions in people if you make them feel like it’s self defense. That pretty clearly establishes Cassandra Nova as a villain, but her threat level increases exponentially when she makes a psychic link with Charles Xavier while he’s using Cerebra (an upgraded version of his telepathy boosting Cerebro helmet). Whomever (or whatever) she is, she’s a powerful enough telepath to pose a serious threat to completely take over Xavier’s mind. She tells him she is going to turn him into a murderer and destroy his dream, but he’s able to force her to leave his mind by threatening to shoot himself.
This woman is clearly bad news. We are then shown that she is in Ecuador because there is a Master Mold Sentinel there that was designed to create adaptive wild Sentinels that would be far more dangerous than the standard variety. She aims to wipe out mutantkind, and she’s going to use these Sentinels to do it. The only problem is that the Master Mold will only respond to members of the Trask family. Now we know why she has brought him here with her. After getting what she needed out of him, she promptly murders him in a way that can only be described as pure unadulterated nightmare fuel.
After a quick battle with Cyclops and Wolverine, she launches a pair of kaiju-sized Sentinels to go to the mutant nation of Genosha and exterminate all sixteen million mutants living there. Though she is successfully captured, the Sentinels are still able to successfully commit the worst genocide in recorded history. She’s brought back to the Xavier School to be imprisoned and studied. It’s revealed that she also has a healing factor along with her telepathic and genetic manipulation abilities, and Beast surmises that she is a new species that has evolved past mutants in the same way that mutants have evolved past humans. She views humans as a dead end species, and mutants are the only true threat to her species’ global superiority. Before anything else can be gleaned, she breaks containment and makes a mad dash to Cerebra. She had intended to be captured in order to get close enough to use it knowing it would allow her to connect to the mind of every remaining mutant on the planet (basically the same thing William Stryker wanted to do in “God Loves, Man Kills” story or the X2: X-Men United movie that would hit cinemas a couple years later), but she ominously says she really only wants to connect with the mind of one particular mutant. Unfortunately for her, Emma Frost snaps her neck and Xavier shoots her to death with a gun before she can go through with her plan. And thus concludes the story of Cassandra Nova.
Just kidding! Turns out she actually succeeded in her plan and connected to the mind of the one mutant she wanted: Charles Xavier. Yes, she had taken over Xavier’s mind and then gunned down the empty husk of her body to throw everyone off the scent. Diabolical! That’s revealed to readers when Beast discovers that Cassandra Nova and Charles Xavier share the same DNA. When he asks Xavier how that could be, Nova reveals that she is Xavier’s genetic twin and has taken over his mind.

She immediately shatters his mind, and then she forces a young mutant named Beak to savagely beat him into a coma. It’s horrific. If the genocide on Genosha didn’t already establish her as one of the most despicable and terrifying villains in X-Men history, then this certainly did. Before the X-Men even have a chance to learn what has happened, Nova summons Xavier’s bird alien girlfriend to come pick her up for a little vacay into space. Nova in Xavier’s body remarks that the destructive power of the Shi’ar Empire in the wrong hands could have disastrous consequences. Not great!
While Nova in Xavier’s body is gone, Beast awakens and is able to explain what happened. Not only did Nova take over Xavier’s body, but she locked Xavier’s mind away in her own corpse. Brutal. Jean Grey and Emma Frost perform a joint telepathic journey into his mind and learn that Cassandra Nova was Charles Xavier’s identical twin that he had tried to murder while in the womb. I love comic books. But wait. If Cassandra Nova is Charles Xavier’s identical twin, why was she identified by Beast as a new species that was the next step in evolution? Don’t worry. We’ll get an answer to that.

Off in space, we see that Nova has been puppeteering Xavier’s body to methodically take control of a Shi’ar Superdestroyer Fleet and command it to head to Earth. That can’t be good.
When Cassandra Nova and the Shi’ar arrive in our solar system, it’s revealed that she has manipulated the Shi’ar (using Xavier’s powerful telepathic powers) into believing that all mutants have been infected with a mental virus by Cassandra Nova and must be exterminated. The X-Men wouldn’t stand much of a chance against the full might of the Shi’ar Imperial Guard on their best day, but they also realize that they’ve all been infected with microscopic nanotechnology Sentinels courtesy of Cassandra Nova that have been steadily weakening their immune systems ahead of the Shi’ar invasion. She really is a diabolical evil genius.
Fortunately, the X-Men are able to convince the Imperial Guard’s strike team that Xavier is actually Nova and they’ve been manipulated. It’s here that we are given a Shi’ar word for what Cassandra Nova is: Mummudrai. In essence, this is described as the anti-self. The very essence of Charles Xavier inverted. It’s something that every person must face and defeat while in utero. A parasite that exists without its own physical body. It’s something that ceases to exist when conquered by most people, but this one was able to access the genome of the most powerful telepath in the world while in the womb and created a body for itself out of his cells. Xavier thought he had killed it, but it survived being stillborn and slowly grew into the thing it is now. Now she’s piloting his body to try and exterminate his own dream. Think they’ll go with that origin story in Deadpool & Wolverine?
Meanwhile, Xavier’s mind is still trapped in what basically amounts to her corpse. Beast thinks he has found a way to rejuvenate the body, but Nova was planning for this. Once she’s finished exterminating all mutants, she’s going discard Xavier’s body and move back into her own. She really seems to have thought of everything. The good news is that Jean Grey is an Omega level telepath bonded to a cosmic deity, so she is able to pull Xavier’s mind out of Nova’s corpse and store it inside her own brain. Classic Jean.
After that, she uses Cerebra to fracture Xavier’s mind into numerous tiny shards and plant them in the minds of every mutant on the planet. When Nova reaches Cerebra and attempts to execute her plan to kill every mutant in the world, she accidentally causes Xavier’s mind to reform and begin reentering his body. Whoopsie! Jean is then able to summon the Phoenix to serve as a kind of cosmic immune system. This forces Cassandra Nova out of Xavier’s body, and she becomes a bodiless being of psionic energy. Desperate, Nova leaps into her old body in hopes that she’s powerful enough to reanimate. That’s when it’s revealed that Emma Frost had laid a trap. The body was actually that of an alien shapeshifter named Stuff that had been part of the Shi’ar strike team. Cassandra Nova was now locked inside an artificial brain that tricked her into thinking she was a student in a classroom being taught by Xavier and Jean. Their plan was to reeducate her and make her amenable to Xavier’s dream of peaceful coexistence.
This is where things get a bit complicated. I realize that implies that things haven’t been complicated up to this point, but that is only because it seems as though future writers either didn’t understand what happened after this or simply chose to ignore it. Cassandra Nova ceases to be the primary villain for the remainder of Grant Morrison’s run despite there being almost thirty issues remaining. In fact, she doesn’t even appear again until the final four issues of the run. Or perhaps I should say that she doesn’t appear in her traditional form until the final four issues of the run. In New X-Men #135 by Morrison and Quitely, a new student at Xavier’s school is introduced named Ernst. Ernst is a young girl who has the appearance of someone much older (much like the telepathic kids from Akira).

We don’t know much about Ernst other than she apparently has super strength, and her best friend is the disembodied brain of a mutant named Martha. She’s pretty shy and socially awkward, and she ends up a member of Xorn’s “special class” that he’s the instructing at Xavier’s school. I bring this up because the final arc of Morrison’s run is a story called “Here Comes Tomorrow” that takes place in a dystopian future where Cassandra Nova has returned and has actually joined the X-Men. In this future, she is always seen alongside Martha’s disembodied brain. She tells Martha at one point that she can still call her “Ernst” if she likes. It’s pretty clear that Ernst is actually the successfully rehabilitated Cassandra Nova even though it’s never explicitly stated in the text. This development really makes her the perfect Grant Morrison character. She is the confluence of both the scientific and the mystical, and she becomes the greatest physical manifestation of Xavier’s dream. Even a genocidal parasite can be rehabilitated. The other thing that makes her a perfect Grant Morrison character is that every subsequent writer who has tackled her has just completely ignored everything Morrison did with her (every Grant Morrison fan reading this is now nodding vigorously).

Cassandra Nova has appeared in exactly three stories since Grant Morrison departed the X-Men line in 2004. She pops up in an arc in Astonishing X-Men #12-18 by Joss Whedon and John Cassaday that ran through most of 2006 where she has planted a piece of her consciousness inside of Emma Frost’s brain and is attempting to use her to try and destroy the X-Men from within. It’s pretty ambiguous what happens to Nova at the end of this arc, but it appears that Emma successfully purges her from her psyche and prevents her from gaining a foothold in the physical world.

The next time she shows up is as the primary antagonist in 2018’s X-Men Red #1-11 by Tom Taylor, Mahmud Asrar, Carmen Carnero, and Roge Antonio. It’s revealed in this series that she has possessed the United Kingdom’s ambassador to the United Nations, and she is once again using microscopic Sentinels to try and destroy mutantkind. The difference this time is that she’s using them to infect humans that she can then telepathically drive to become anti-mutant bigots hellbent on committing genocide. Her plan is hilariously thwarted by mass producing replicas of Magneto’s helmet that prevent her from communicating with her brainwashed victims. She is ultimately defeated when Jean Grey is able to get into her mind and cause her to feel empathy for the first time. This is at odds with how Morrison’s New X-Men run concluded, but it at least puts Cassandra Nova back on the path to rehabilitation.

The most recent appearance of Cassandra Nova came in the pages of 2022’s Marauders #1-10 by Steve Orlando, Eleonora Carlini, and Andrea Broccardo. In this series, it’s revealed that Cassandra Nova has been living on a quarantined area of Krakoa and is back to being mostly sadistic. She is recruited to join Kate Pryde’s team of Marauders to go back in time two billion years to save a lost civilization of mutants from extinction. Pretty typical stuff. Cassandra Nova’s immense powers help the Marauders succeed in defeating a powerful enemy duo of Sublime and Arkea, but she is then immediately betrayed by the rest of the Marauders and stranded two billion years in the past as revenge for the genocide in Genosha all those years ago. It’s wild stuff. That is the last we have seen of Cassandra Nova at this point.

Now she’s going to be in Deadpool & Wolverine. Can’t say I saw that coming. I have no idea how large of a part she will actually play in the movie or how much of her comic book backstory will be adapted, but now you’ll at least know why comic book readers like me will nerd out in the theater when she appears on screen this weekend.
This was a fun read!