Matt Reeves’ The Batman made a killer splash with audiences and critics. Shortly after the film’s release, Warner Bros. revealed it had no less than three HBO Max spin-off series in development. The most notable one focuses on Colin Farrell’s Penguin character. Additionally, a Gotham PD spin-off was ordered but was ultimately shelved; it is shifting now to Arkham Asylum. This new direction has an opportunity to expand Batman’s rogues’ gallery for the Reeves universe in a fun, creative way.

From Forbes, Reeves said about the project:

“We’ve actually now [moved] more into the realm of exactly what would happen in the world of Arkham as it relates coming off of our movie and some characters and their origins…almost leaning into the idea of, it’s like a horror movie or a haunted house that is Arkham.” Reeves said.

The Batman has already featured Paul Dano’s brilliant and sinister iteration of Riddler, the aforementioned Penguin, and Catwoman, played by Zoey Kravitz. In late March of 2022, fans were treated to a deleted scene featuring a terrifying Joker played by Barry Keoghan. DC Studios’ creative head James Gunn has recently confirmed that this series will take place in the DCU and not Reeves’ Batman universe as it was originally planned to, meaning that the possibilities are endless with what villains are showcased ahead of The Brave and the Bold. The speculation will only widen with time, as it does remain unclear exactly what universe the Arkham series will reside in.

But who do fans need to see? Who do they want to see? In the pantheon of live-action adventures of the World’s Greatest Detective, portrayals of villains have been warmly received or coldly despised. With this alternate version of Pattinson’s Batman being set on Earth 2, the choice of villains not featured in the film is up for grabs. The expectations will undoubtedly fluctuate depending on which villains the series chooses to introduce. Rumors have circulated about Mr. Freeze or Court of Owls (finally) appearing in a future feature film. But here are some villains who should get the spotlight.

Updated January 18, 2024: This article has been updated with even more villains that should appear in the highly anticipated Arkham Asylum series.

Killer Croc
DC Comics, Inc.

A Batman foe that has yet to reach full potential outside the comics and animated adventures is Killer Croc. Formerly known as Waylon Jones, Killer Croc turned to a life of crime due to his rare genetic condition, which left him feeling ridiculed and isolated, finding work as a sideshow entertainer. While often resigned as only a physical challenge for Batman, his inclusion in the Arkham series could allow for some on-screen character development. His physical stature and ghastly reptilian appearance would be an interesting addition to the otherwise grounded nature of The Batman.

Killer Croc previously appeared in 2016’s Suicide Squad, played by Adewale Akinnuoye-Agbaje, but much like the film he appeared in, that version of the character left much to be desired. An inclusion in an Arkham Asylum television series could explore the character’s isolation and move him beyond just being a physical opponent for Batman to a tragic figure.

Clayface
DC Comics, Inc.

This particular character has undergone several incarnations (and aliases) throughout his 80-plus year existence in Detective Comics. The more popular version of Clayface, actor Basil Karlo, has shown his creative shape-shifting abilities to be a frustrating pain for the Dark Knight. Driven mad when he was excluded from a remake of the horror film that put him on the map, he becomes a serial killer, taking up the Clayface identity from the movie to seek his twisted retribution. If he makes an appearance in the show, it wouldn’t be surprising if the creators tapped into his first shade of villainy. This would have him appear as a serial killer borrowing the identity of a horror movie villain, symbolically transforming into another person instead of physically morphing into them.

With rumors of The Batman: Part II introducing Clayface, if the series is set within the Reeves film the new series could potentially lay the groundwork for his role in the upcoming film or pick up after. With so many different Clayfaces, some with no abilities while others have superpowers, he can fit within either Reeves grounded universe or the more fantastical DCU. As the resident monster in Batman’s rogues’ gallery, he can be a terrifying villain that would very much fit the series’ tone. The one thing about Clayface is that, while he’s one of the more exciting villains visually, he’s rarely given the depth he deserves as a character. The Arkham series would be the perfect opportunity to analyze Karlo as the man beneath the mud.

Harley Quinn
Warner Bros.

Harley Quinn is one of DC’s most popular characters, and since she got her start as a doctor at Arkham Asylum, a series set in it could be a great origin story for The Batman incarnation of the character. With Barry Keogan as The Joker, an Arkham Asylum series with Harley Quinn could feature an entire season arc adaptation of “Mad Love”, seeing her transformation from a psychiatrist to becoming the Joker’s partner. While Lady Gaga is set to play the character in Joker: Folie à Deux, that version is outside either DC universe, so there is more room for interpretation.

Related: How Harley Quinn Went from Sidekick to Leading Lady

As for if the series is set in James Gunn’s DC Universe, it could be used to reintroduce Margot Robbie as Harley Quinn or make a clean break and set up a new incarnation of the character. It is unknown if Robbie will return, but there cannot be a DC Universe without Harley Quinn in it, so that decision will need to be made soon.

Calendar Man
DC Comics, Inc.

A character often overlooked and underappreciated, Julian Gregory Day, a.k.a. Calendar Man, at first, doesn’t seem like a villain worth plucking from the gallery. Ironically, that is Calendar Man’s best trait. His innocuous and subtle existence dials down his importance, especially against all the other headliner baddies that usually encounter Batman. His high-level intellect made him an asset à la Hannibal Lecter-style for the Caped Crusader during the run of The Long Halloween. His obsession with dates, holidays, and sometimes murder still fits the nuanced wackiness of the other villains introduced thus far in The Batman. His appearance as a mental opponent for Batman could even rival that of Riddler.

Calendar Man is the quintessential Arkham inmate. He’s as straightforward of a killer as Gotham gets and has been transformed into a criminal mastermind in recent years. He slots perfectly into the Arkham series as one of the smartest villains in the asylum. He’s often consulted about other criminals due to his knowledge of how the underworld operates and could fill a similar position in this series. Calendar Man is the guy Gordan or Batman go to when they need information, and he’s happy to help when it benefits him.

Mad Hatter

Jervis Tetch grew up captivated by Lewis Carroll’s Alice in Wonderland book to the point where he thought he was the Mad Hatter himself. While he started out as an expert neuroscientist, he took that knowledge and put it towards his world of delusion. Tetch fully embraced this idea of who he truly was and devoted his life to crime, mostly themed around his prized book stories and finding his one true Alice. He used his skills in the science fields to develop mind-control technology, which he often uses to send Batman on an otherworldy and hypnotic trip down the rabbit hole.

As a character suffering from mental health issues, it could be interesting to explore how Arkham treats those patients. It’s obvious that the establishment is often corrupt and/or underfunded without the necessary resources to treat its patients, and Tetch is a prime example of that. With the series looking to showcase these criminals, there’s room to see how the Mad Hatter came to be and if there’s any way to help him. As someone who’s dealing with paranoid schizophrenia, it’s still possible for him to get the help he needs. It’ll take a lot of work, but after some medication and therapy, it’s possible to reform the Mad Hatter back into brilliant scientist Jervis Tetch. Showing this different side of Batman villains in the asylum as they get the help they truly need is a fresh take that offers a new perspective on the Batman mythology.

Professor Pyg
DC Comics, Inc.

One of the newest Batman villains, making his first appearance in 2007, Professor Pyg has already risen up the ranks to become the most disturbing in his rogues’ gallery. His real name is Lazlo Valentin, but besides that, little is known about Pyg’s true background and upbringing. What’s clear about him, though, is his obsession with making everyone “perfect”. Pyg is a serial killer who kidnaps and horrifically murders innocent Gotham citizens and turns them into his “Dollotrons”, perfect minions that obey his every word. His grotesque surgeries remove what makes a person unique to consider then them perfect in his eyes. While not a physical match for Batman, he is severely deranged and with an army of Dollotrons by his side, a force in Gotham that needs to be reckoned with.

Professor Pyg is exactly the kind of character that was made to be in the Arkham series. If Reeves is aiming for a horror tone, then look no further than him. Pyg’s crimes speak for themselves in showing how haunting he can be, and he is routinely arrested at the asylum. The unhinged killer stands out from other villains due to the mystery surrounding him and his lack of reason. Batman has worked alongside some of his greatest foes before, but someone as inhumane as Professor Pyg is beyond rehabilitation. It makes him the kind of compelling character that could be dug into in a series all about Arkham Asylum and if its methods are even viable.

Maxie Zeus
DC Comics

Maxie Zeus is certainly one of Batman’s sillier villains. Introduced in 1979, he is a former history teacher who loses his grip on reality after the loss of his wife. He eventually becomes a crime lord who believes himself to be the real Zeus of Olympus, which, given characters like Wonder Woman and Shazam in the DC Universe, is certainly not that unbelievable. While he is just a normal man and not seen as big of a threat in the comics, there are two reasons why he would fit within either the grounded world of The Batman or Gunn’s DCU.

For Reeves more grounded reality, Zeus could draw from his depiction in the comic Arkham Asylum: A Serious House for a Serious Earth, an emaciated patient perpetually receiving electrical currents, which he believes to be fire from heaven. This is certainly a more psychologically damaging take on the character, a man drawn to pain. Yet the belief in the Greek Gods of Olympus could be used for world building in James Gunn’s DCU to set up the new Wonder Woman and play off Phase 1 theme “Gods and Monsters”.

The Ventriloquist
DC Comics, Inc.

Arguably the most underrated of Batman’s villains, The Ventriloquist is a tragic character and the epitome of Gotham’s poor mental health system. Arnold Wesker is a quiet older man on the surface but is inseparable from his puppet Scarface. In his eyes, Wesker has no choice but to listen to the puppet and carry out the horrific crimes it demands. To the rest of the world, people think he’s using it as a front to carry out evil deeds and blame Scarface for it all. The truth is much sadder, being that Wesker was diagnosed with dissociative identity disorder and the system failed him. This manifests through the puppet as he takes out his pent-up frustration on a city that wasn’t there for him, becoming a ruthless crime boss.

Related: The 10 Darkest Batman: The Animated Series Episodes

To do an Arkham-centric series right, it’s important to highlight the failures of the asylum. There’s no better character to do this with than the Ventriloquist. Arkham’s lack of resources for helping people with mental health issues directly leads to him becoming a criminal. It was entirely avoidable for Wesker if he had the right therapist to help him process the trauma he went through, but unfortunately, Gotham is not a kind city to those struggling with their mental health. Portraying that through the Ventriloquist gives him a purpose in the series and could even make the audience sympathetic towards his situation. Perhaps his experience could even lead to substantial change by the end of the series.

Hugo Strange
DC Comics, Inc.

It’s impossible to talk about Arkham Asylum without mentioning its twisted mad scientist, Hugo Strange. One of Batman’s earliest villains, debuting all the way back in 1940 and predating the Joker, Strange saw Batman as the problem rather than the solution to Gotham’s problems. To him, Batman’s existence wasn’t keeping the streets clean, rather he was fueling the fire that was crime itself. Strange has become obsessed with learning his true identity to expose him for the fraud he is and even potentially take his place to properly fix the city. Despite being a genius psychiatrist in his own right, his fixation on Batman drove him mad to the point where he’s willing to do whatever it takes to stop him.

It’s a no-brainer to see how well a character like Hugo Strange would fit into Matt Reeves’ Batman universe. He works well in a grounded setting and is a genuinely terrifying threat. Unlike other Batman villains, Strange is more mental than physical and is entirely focused on replacing the Dark Knight. Whether he’d be a doctor in the Asylum experimenting on his patients and turning them into monster men or sent there after losing his own mind, there needs to be a place in the series for Strange. The possibilities are endless with a character this versatile and could serve as another mental challenge for the Caped Crusader down the line.

Victor Zsasz
Victor Zsasz

It might be easy to chalk Victor Zsasz up as just another loose-cannon serial killer. To be fair, that is what he is. But in arguably the greatest live-action Gotham setting seen yet, it would be a crime not to introduce a sadomasochistic supervillain who would deftly round out the batch of true-crime-esque adversaries seen thus far. Zsasz has been in Batman stories for decades, displaying self-imposed carvings on his body tallying up his number of victims. Given his origin as a man who loses all financial capital in spectacular fashion – in the Iceberg Lounge headed by Penguin, no less – his menacing existence as a wild card would fit right in for this universe.

Reeves is clearly interested in exploring the crime-noir side of Batman mythology, and a villain like Zsasz fits perfectly into that setting. Arkham is practically his home away from home, as nobody has spent more time incarcerated there than he has. If the series is going to focus on the inmates in the Asylum and what makes them tick, Zsasz would be a fascinating character to explore. He kills to “free” people from what he views as a pointless existence, and taking a deep dive into a character like that could make for a very interesting story.

While there are many other worthy adversaries that have taken residence in Arkham Asylum in the span of Batman’s adventures, this starter pack would provide a variety of strengths to challenge justice in Gotham. The spread here is quite mixed between the brainy and brawny, the crazy and the crazier. There are many opportunities with this small set of villains for strong but short story arcs with satisfying pay-offs. The success of Zsazs’ and Calendar Man’s inclusion is baked in with the established noir atmosphere that Reeves has created. The biggest gamble would be Clayface or Killer Croc, undoubtedly. No matter which villain shows up in this new Arkham series, it is assured they will leave a lasting mark on an already impressive ensemble.