
Long before the first trailer finally dropped for Spider-Man: No Way Home and people glimpsed the many villains featured in the trailer, there has been lots of speculation about the villains. Specifically, the Sinister Six, the villain group comprised of Spider-Man’s most famous enemies. The trailer showed at least one member of that group and the trailer showed evidence of other members, which came to five. So, who is the sixth member of the Sinister Six in the film?
First off, let’s clear the air, it is doubtful we will get a faithful version of that group first seen in The Amazing Spider-Man Annual #1. That line-up consited of Doctor Octopus, Kraven the Hunter, Mysterio, the Vulture, Sandman and Electro and they formally combined their forces to take on their mutual enemy, though they did so rather stupidly. Instead of teaming up together and taking out Spidey at once they decided to confront him one by one during separate occasions, which gave him a chance to defeat them individually. From looking at the trailer it appears as if the Sinister Six is not a formal group, but a collection of foes that plague Spidey.
Getting back to the main question, let’s go over who will appear. According to reports, aside from Doctor Octopus who made an appearance and Green Goblin, as evidenced by a pumpkin bomb, the other three villains were Electro, the Lizard and Sandman. The latter three were only hinted at and noticed by careful examiners of the trailer. These villains were featured in previous Spider-Man films and that could provide an answer to the sixth member. The other Spider-Man films featured Venom, Rhino, Shocker, Vulture, two versions of the Green Goblin based on Harry Osborn and Mysterio.
While Spider-Man has an impressive rogues gallery with foes who have not appeared in live action yet, it’s doubtful we will see them in Spider-Man: No Way Home. To include one of them at this point would not make sense because they haven’t had the exposure to have an impact when they appear. That, unfortunately, leaves out classic foes like Kraven or Chameleon or the Scorpion. These three would have made a great impact in a more grounded Spider-Man film that followed up the events of Spider-Man: Far From Home and fully explored the ramifications of Spider-Man’s identity being exposed. Instead, the new film will explore the Multiverse concept of the Marvel Cinematic Universe (MCU) and other cinematic universes based on Marvel characters. On the other hand, the Scorpion’s alter ego, Max Gargan, was introduced in the first MCU Spider-Man film which hinted at his returning to menace Spidey. Spider-Man: No Way Home could be used to further develop Gargan after he is turned into the Scorpion.
If this doesn’t happen in Spider-Man: No Way Home then the two other logical choices for the sixth member are either the Vulture or Mysterio. This version of the Sinister Six so far includes Spider-Man enemies not seen in the MCU and needs someone from the MCU to tie the MCU version of Spider-Man more closely to the group.
It’s possible both villains could appear in Spider-Man: No Way Home but it will most likely be just one, but who? Vulture has more personal ties to Spider-Man and his alter ego. Plus, he appeared in the trailer for the Sony/Marvel film Morbius so this film could further establish ties to Morbius. Mysterio returning would make sense, even though he was killed in Spider-Man: Far From Home. However, given his dubious nature and talent for misdirection, it is likely he faked his own death and give the MCU Spider-Man the chance to deal with him once and for all.

Then again the film could throw us off completely and give us Venom or someone completely unexpected like Morlun or the Hobgoblin. We’ll find out in just a few short months. Let the speculation continue until then!