WARNING: The following article contains spoilers for Sony's Spider-Man: Into the Spider-Verse, in theaters now.

Spider-Man: Into the Spider-Verse is a love letter to its comic books source material that explores what it means to be the iconic superhero, in his (and her) many forms. But while the film possesses some obvious similarities to Marvel Comics' 2014 "Spider-Verse" storyline, by Dan Slott and Oliver Copiel, there are some major differences between the two

One of the biggest changes is the villain who unites the Spider-heroes from across the multiverse. While the film grounds the threat in Wilson Fisk's determination to reunite with his dead family, the comic book focuses on a group of immortal vampiric people hunting "Spider-Totems." Allow us to explain.

The Inheritors

The Inheritors were technically introduced in The Amazing Spider-Man Vol. 2 #30, by J. Michael Stracynski and John Romita Jr., with the debut Morlun as one of the most dangerous threats that has ever faced Peter Parker. He’s drawn to the Spider-Totems, people empowered -- through either magic or science -- with spider-powers. When he get his hands on anyone with those abilities, he drains them of their life essence.

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Morlun turns out to be practically unstoppable, with Peter only barely beating him in their first battle. The character's introduction didn’t contain any indication his family is just as dangerous as he was, but Slott brought them back as the primary villains of the "Spider-Verse" event.

In the build-up to that storyline, the rest of his family was introduced as an equally powerful assortment of villains. Their immortality was revealed to be derived from an advanced cloning system that allows them to come back from death with their memories and experiences intact. Together, they lay waste to an assortment of Spider-heroes across the multiverse, making up the majority of the conflict in "Spider-Verse" as the remaining Spider-heroes unite to fight them.

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Their patriarch Solus was killed in battle by Kaine (a clone of Peter Parker who serves as his occasional foil), and the other Inheritors were trapped on the ruins of an alternate Earth, unable to escape a solitary bunker without being overwhelmed by the radioactive fallout. However, they returned earlier this year in Marvel's "Spider-Geddon" event, where they went to war once again against the Spider-heroes.

The Differences Throughout

The Inheritors don’t factor at all into Spider-Man: Into the Spider-Verse. None of them appears in the film, where the primary antagonist is instead Wilson Fisk, better known as Kingpin. By altering the villain's motivation, from senseless destruction to the hope of a reunion with dead loved ones, the film echoes the loss experienced by most of the Spider-heroes.

Despite his actions leading to the potential destruction of New York City, and potentially his entire reality, Fisk is committed to regaining the family he lost. If that means blasting a hole through reality to find alternate versions of them, then so be it. It’s a fundamental change that greatly impacts the story, making the plot more directly connected to the growth of the main characters while leaving intact the basic premise -- that is, Spider-heroes uniting from across the multiverse.

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It admittedly helps to ground the movie (a strange notion, admittedly, given that it involves Spider-Ham, an anthropomorphic pig) by keeping events confined mostly to a single reality. The film also reduces the number of heroes, taking a venerable army of Spider-powered characters down to six (plus a robot).

Although the Inheritors don't make their big-screen debut in Into the Spider-Verse, we may not want to count them out just yet. Elements of the original comics slip into the post-credits scene, particularly in the reality-jumping watches constructed by Miguel O'Hara, which could be key to the Spider-heroes combating the Inheritors, should they make their presence felt in a sequel or spinoff.

The (Potential) Arrival Of The Inheritors

With the confirmation that the Spider-heroes will be for for future films, the ending of Into the Spider-Verse implies they will have to unite in the future for some unknown threat, which could easily turn out to be the Inheritors. Given that a planned spinoff will team Gwen Stacy with Jessica Drew and Silk, it's certainly possible the villains will rear their heads there.

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After all, the three heroes teamed up in one of the major comic book tie-ins to Marvel's "Spider-Verse" to sneak into the Inheritor base, so there’s a chance that even though the Inheritors didn't arrive in this Spider-Verse film they certainly could be bound for another one.

Directed by Bob Persichetti, Peter Ramsey and Rodney Rothman, Spider-Man: Into the Spider-Verse stars Shameik Moore, Brian Tyree Henry, Jake Johnson, Mahershala Ali, Hailee Steinfeld, Liev Schreiber, Luna Lauren Velez, Lily Tomlin, Nicolas Cage, John Mulaney and Kimiko Glenn. The film is in theaters now.