The Marvel Cinematic Universe benefited immensely from the an overarching villain to serve as connective tissue between films, and to help build anticipation toward the inevitable showdown. Throughout the Infinity Saga, Thanos was revealed to have been puling the strings since before his introduction in the mid-credits scene of 2012's The Avengers. The Mad Titan's death in Avengers: Endgame was so satisfying for audiences because of his seven-year arc, which built up, and flesh out, the threat he posed with appearances in six films.
With Sony attempting to build its own "Spider-Verse," referred to internally as Sony's Universe of Marvel Characters, linking such Spider-Man ancillary characters as Venom, Morbius the Living Vampire and Kraven the Hunter, and now, it seems, the wall-crawler himself, the studio would do well to look at the Marvel blueprint for building a cinematic universe-spanning antagonist.
The Spider-Man comics have numerous colorful, and formidable, villains that have yet to make their big-screen debut, so there has to be a character out there that could fill a Thanos-type role.
Audiences got their first look at Woody Harrelson's Cletus Kasady in the mid-credit scene of Venom. The red-headed serial killer is locked up in prison when Eddie Brock (Tom Hardy) arrives to interview him. Things quickly turn ominous as Kasady promises "carnage" upon his escape from his cell. The tease was a clear indication that Harrelson's villainous character has a future in the franchise.
It was recently confirmed by Venom 2 cinematographer Robert Richardson that Kasady will return for the sequel. With an A-list actor already attached to the role, using Carnage as the overarching villain for the inevitable team-up between Venom, Jared Leto's Morbius and, potentially, Tom Holland's Spider-Man seems like an obvious choice.
MORLUN AND THE INHERITORS
An under-the-radar pick for the major threat of the SUMC would be Morlun, a deep-cut Marvel foe who's a member of the supervillain group the Inheritors. First appearing in The Amazing Spider-Man Vol. 2 #30, Morlun is a superhuman entity who travels the multiverse in search of Spider-Totems (that is, mystical items across the multiverse that grant people with powers similar to Spider-Man's). He served as the antagonist for the "Spider-Verse" storyline, in which the Inheritors attempt to kill all the versions of Spider-Man in the multiverse.
Using Morlun and the Inheritors as an overarching threat could help with some of the issues that plagued Venom. The SUMC's first entry relied heavily on CGI battles, which tends to diminish the emotional element of such confrontations. Using a group of human-like villains could help audiences to connect to the characters, something that's lacking in many comic book adaptations.
KNULL THE SYMBIOTE GOD
Another little-known supervillain who could serve as the Thanos of the SUMC is Knull, an evil deity who created the All-Black, the first symbiote. Although he's only been in the pages of Marvel Comics for less than a decade, Knull has become a formidable opponent for even the likes of the Silver Surfer.
If Sony decides to further embrace the symbiote story in Venom 2, setting up Knull as the main protagonist of the franchise seems like a smart move. For a team-up of villains to be necessary, there must be a threat so daunting that the bad guys have to put their differences aside. Knull seems a near-perfect fit, as there isn't another character in the Spider-Man lore that could take on Venom, Carnage and Morbius, all at once.
Directed by Andy Serkis and starring Tom Hardy as Eddie Brock, Venom 2 does not yet have a release date.