Ghostbusters 4 (2023) is less than a year away, and though the filmmakers have told us that the upcoming sequel will “continue the Spengler family story” established in Ghostbusters: Afterlife (2021), it’s possible the film will also be the most ambitious instalment in the franchise.
With the multiverse concept continuing to trend in cinema, in films such as Marvel and DC, Ghostbusters could end up introducing its very own multiverse in Ghostbusters 4. The wider franchise is no stranger to it, as it’s often used in IDW’s long-running comic book series.

Related: 5 Huge Updates From ‘Ghostbusters: Afterlife 2’
So, is it possible that characters from the divisive 2016 reboot, for example, will show up in the sequel? Well, could you ever have imagined Andrew Garfield returning as Peter Parker/Spider-Man? After all, The Amazing Spider-Man films are hardly beloved by fans!
It’s not all about the reboot, though — there are characters from other corners of the Ghostbusters extended universe, such as the comics, the video games, and the animated shows. We don’t currently know anything about the plot for Ghostbusters 4, but this remains a huge possibility.
So, here are seven characters — some from the wider Ghostbusters universe — who could change everything if they appear in the upcoming sequel..
1. Lady Slimer

Slimer is among the most iconic Ghostbusters villains, although in beloved ’80s cartoon The Real Ghostbusters (1986), the “ugly little spud” is actually a friend of Janine Melnitz, Winston Zeddemore, Peter Venkman, Ray Stantz, and Egon Spengler.
But there are two things people don’t realize about Slimer — he’s the only character who has appeared in the main Ghostbusters movies and the reboot Ghostbusters: Answer the Call (2016), and also, both he and his love interest Lady Slimer were played by the same actress!

The wonderful Robin Shelby brought Slimer to life in costume in Ghostbusters II (1989), and later provided the voice for Lady Slimer in the 2016 reboot. As such, the incredibly talented actress deserves another shot in Ghostbusters, but we’d like to see Lady Slimer back in the fold!
In fact, having her back could be a wise move for the series. Seeing as Slimer has “visited” both Ghostbusters timelines, going from the main films to the reboot, it would only make sense for Lady Slimer to do the opposite, and in doing so, open the doors to the Ghostbusters Multiverse!
Related: The 2016 Reboot Wasn’t the First Female-Led ‘Ghostbusters’
2. Kylie Griffin

Fans who are only really familiar with the Ghostbusters films won’t necessarily recognize the name Kylie Griffin, because, to this day, she’s a character from the Ghostbusters extended universe who’s yet to get her shot in live action.
Kylie Griffin (Tara Strong) is a Ghostbuster from gritty animated show Extreme Ghostbusters (1997), the follow-up to The Real Ghostbusters. But while she’s a fan-favorite character within the wider fanbase, she’s relatively unknown in the more mainstream Ghostbusters media.

Though it expanded the franchise in new ways, Ghostbusters: Afterlife missed the opportunity to bring Griffin to life in live action. In IDW’s “Ghostbusters” comic book series, Griffin works with Ray Stantz at his bookstore Ray’s Occult Books, which actually appears in the 2021 film.
Having a character who has appeared in both an animated show and the comic book series could enrich Ghostbusters in ways like never before, and it would also give us another established Ghostbuster character besides all the ones we’ve long become familiar with.
Related: 5 Things Fans Expect From ‘Ghostbusters 4’
3. Walter Peck

Walter Peck has also appeared in more than one medium of storytelling within the Ghostbusters universe. He’s the main human antagonist in the original Ghostbusters (1984), played by the brilliant William Atherton, and he also appears in IDW’s long-running comic book series.
The comics follow the events of the first two films, in which Walter Peck, former inspector for the EPA (Environmental Protection Agency), has since gone on to lead the Paranormal Contracts Oversight Commission, an agency that oversees the Ghostbusters.

That’s right — in the comics, Walter Peck is in charge of the Ghostbusters (of course Venkman isn’t happy about it, what a silly question). And it isn’t too late to bring Peck back into the fold in the upcoming Ghostbusters: Afterlife sequel, either, which will return to its New York City roots.
His comeback wouldn’t need to follow the comics down to the letter, but like many others, Peck is a beloved character, despite the fact he causes a great deal of trouble for the Ghostbusters in the original film! We wonder if they ever did send him a nice fruit basket…
Related: All the Main Villains in the ‘Ghostbusters’ Movies Ranked Worst to Best
4. Erin Gilbert

If you weren’t surprised by the suggestion that Ghostbusters 4 should include the return of the very mischievous Lady Slimer, you might fall off your chair at the mere sight of seeing a human character from the highly controversial reboot on our list!
The truth is that, while Answer the Call was unfortunately met with a prickly reception upon release, and didn’t go on to capture quite as many big bucks in its stream as Sony Pictures would have liked, the film had a lot of potential, and is still in possession of many salvageable parts.

One of them is particle physicist and author Erin Gilbert (Kristen Wiig), who’s really the main character in the film, and is, for all intents and purposes, the “face” of the Ghostbusters, just like Peter Venkman (Bill Murray).
Erin has a very interesting backstory where the paranormal is concerned, although this is only fully explored in the film’s tie-in novel by Nancy Holder. Either way, bringing her back for Ghostbusters 4 would change everything. Where there’s a multiverse, there’s a way!
Related: The Fifth ‘Ghostbusters’ Movie Could Feature Characters From the 2016 Reboot
5. Louis Tully

There might be no other character in the Ghostbusters films who’s quite as loved as Louis Tully (Rick Moranis). In the first two films, Louis is an eccentric accountant who becomes good friends with Dana Barrett (Sigourney Weaver), Janine Melnitz (Annie Potts), and the Ghostbusters.
When he isn’t transforming into the Keymaster/Vinz Clortho, he can be found acting as the Ghostbusters’ completely inept defense attorney! Rick Moranis gives an adorable performance as Tully, and while he’s not from the Ghostbusters extended universe, we simply want him back!

Fans were expecting to see Moranis reprise his role in Afterlife, but unfortunately, the actor stepped away from Hollywood a long time ago following the tragic passing of his wife. With that said, he is reportedly involved with the Honey, I Shrunk the Kids (1989) Disney+ series.
Is it possible then, that Louis Tully will return for Ghostbusters 4? Only time will tell, but with the series now back in New York City, anything is possible. In the meantime, you can always check out the IDW comics, in which Tully is a recurring character.
Related: Female Ghostbuster Makes Surprise Return In New ‘Ghostbusters’ Trailer
6. Jennifer “Jenny” Adams

Another character from the original Ghostbusters who also went on to appear in the IDW comics is Jennifer “Jenny” Adams (Jennifer Runyon). Although, in the film, she’s credited simply as “Female Student”, as she has only a small role opposite Peter Venkman (Bill Murray).
Jennifer appears in the scene in which Peter is conducting an experiment that tests the effects of negative reinforcement on ESP (extrasensory perception), which Afterlife pays homage to, as Dana Barrett conducts the same test on Peter in a mid-credits scene.

While Jennifer’s appearance in the film is short-lived, she does appear in the IDW comics. There are many references to her character throughout the long-running series, and she makes her long-awaited return in “Ghostbusters International”, in which her name is also finally revealed.
Having Jennifer return in Ghostbusters 4 would be a very wise move. Not only would it be great to see the amazing Jennifer Runyon back in the series, but the revelation that her character does have ESP could expand the lore in new ways, as she would be the first character with such talents!
Related: 7 Bizarre Facts You Didn’t Know About ‘Ghostbusters’ (1984)
7. “Rookie”

Since the release of Afterlife, there has been some speculation around whether or not Ghostbusters: The Video Game (2009) is still canon. Fans have widely considered the game to be a sequel to the original films, something even Dan Aykroyd confirmed many years ago.
The game even features the return of several actors from the films — Bill Murray (Peter Venkman), Harold Ramis (Egon Spengler), Ernie Hudson (Winston Zeddemore), Annie Potts (Janine Melnitz), and Dan Aykroyd himself (Ray Stantz).

However, as the 2021 sequel seemingly contradicts certain events that take place in the game — which is set in New York in 1991 — it’s possible that it is indeed no longer part of the primary Ghostbusters continuity. But this is something that could be easily remedied in the new film.
The game’s only playable character is a new Ghostbuster cadet whose designation is simply “Rookie” (Ryan French). He doesn’t speak, although, like many other characters on this list, his efforts are called upon again in the comics, in which he goes on to lead “Ghostbusters Chicago”.
With Ghostbusters 4 preparing to film in London, is it possible the franchise will use the “Ghostbusters International” storyline from the comics? If so, Rookie would be a great tool to help properly connect the film series to the 2009 game again, and at the same time, the comics.

Related: All Upcoming ‘Ghostbusters’ Movies, TV Shows, Comic Books and More
As per the Ghostbusters/Sony Pictures website, here’s the synopsis for Ghostbusters: Afterlife:
From director Jason Reitman and producer Ivan Reitman, comes the next chapter in the original Ghostbusters universe. In Ghostbusters: Afterlife, when a single mom and her two kids arrive in a small town, they begin to discover their connection to the original ghostbusters and the secret legacy their grandfather left behind. The film is written by Jason Reitman & Gil Kenan.

Related: All 13 Ghostbuster Characters (Including a Guest of Honor!) Ranked Worst to Best
Ghostbusters: Afterlife stars McKenna Grace (Phoebe), Logan Kim (Podcast), Celeste O’Connor (Lucky), Finn Wolfhard (Trevor), Carrie Coon (Callie), Annie Potts (Janine Melnitz), Sigourney Weaver (Dana Barrett), Paul Rudd (Gary Grooberson), Olivia Wilde (Gozer the Gozerian), JK Simmons (Ivo Shandor), Bill Murray (Dr. Peter Venkman), Dan Aykroyd (Dr. Ray Stantz), and Ernie Hudson (Winston Zeddemore).
Ghostbusters 4 will be released on December 20, 2023.

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Do you think any of these characters will return for Ghostbusters 4? Let us know in the comments down below!