If a clue in the Fallout season 1 finale is any indication, a major character may be transforming into the show’s biggest missing monster.

A Fallout theory postulates that Thaddeus will transform into a super mutant when the Prime Video series returns. Introduced as a member of the Brotherhood of Steel in Fallout’s show, Thaddeus became a source of humor as he began acting as a servant to the person he once bullied. But as Fallout’s story unfolds, it becomes apparent that Thaddeus’ life will get much worse before he gets better. The series has strongly hinted that Thaddeus is about to undergo an unsettling transformation.

In Fallout episode 7, Thaddeus injected himself with a serum from an unscrupulous doctor. Due to what’s known about the doctor, there was good reason to suspect that the injection wasn’t at all what it appeared to be. Fallout supported that assumption when it revealed that Thaddeus had developed an inhuman resistance to injury. Maximus himself acknowledged that Thaddeus seems to be turning into one of Fallout’s ghouls. But while this was the impression that Fallout gave, it’s possible that the series is actually gearing up to turn him into a different creature, one that it teased but didn’t fully introduce.

Why Thaddeus May Turn Into A Super Mutant In Fallout Season 2

Thaddeus may have been injected with FEV

While it may be that Thaddeus is indeed in the process of becoming a ghoul, that’s not the only Fallout monster that fits in with the show’s setup for his transformation. In fact, it would make more sense if Thaddeus was changing into a super mutant instead. It’s important to note that there’s nothing in the pre-established lore that would explain how the serum could turn Thaddeus into a ghoul. Such a transformation is something that happens due to prolonged radiation exposure. While it can be induced by scientific means, Thaddeus’ changes are happening a bit too fast to align with the current understanding of ghoul biology.

Thaddeus’ ongoing transformation would, however, line up with what’s been established about super mutants. In Fallout’s world, super mutants were humans morphed into monsters by scientific experimentation. Some are the product of a formula called FEV (Forced Evolutionary Virus). After being injected with the FEV serum, test subjects would transform into super mutants. The liquid that the doctor gives Thaddeus being revealed as FEV would provide a working explanation for what the character is going through. Super mutants are incredibly resilient, so Thaddeus not feeling pain matches up with that detail in the show as well.

Fallout Already Teased The Creation Of FEV

Fallout’s Vault-Tec meeting set up West-Tek’s plan to make super mutants

The prospect of Thaddeus becoming a super mutant via FEV is made even more likely by a key scene in the Fallout season 1 finale. One of the characters in Fallout’s Vault-Tec meeting is revealed to be Leon Von Feldon, an executive at West-Tek, one of the many science corporations in the universe of the games and the series. When Barb Howard tells the company representatives they can do with they want with their vaults and that no one will ask questions, each character brings up their own ideas,with Leon Von Feldon specifically mentioning an interest in producing “super mutant” soldiers.

This comment coming from a West-Tek executive may have major implications on Thaddeus’ story. After all, it’s West-Tek that designed FEV in the first place. FEV is how West-Tek made the super mutant monster, meaning that this is what the show is foreshadowing. Fallout choosing to reference the creation of FEV in particular here is telling, considering that in the episode prior, a character was injected with a serum that could very well have been the Forced Evolutionary Virus. The show choosing to highlight West-Tek’s plans only bolsters the evidence for the theory that Thaddeus has FEV.

What Thaddeus Being A Super Mutant Could Mean For Season 2

Thaddeus will have the upper hand if he meets Lucy or Maximus again

By making Thaddeus into a super mutant, Fallout would be able to pay off all its teases to the monster. Though super mutants are common opponents for the Vault Dweller in the Fallout games, the show has been carefully avoiding them thus far. The show certainly hasn’t been oblivious to them, though, since there were a few moments where it appeared that Fallout was intentionally hiding them. For instance, there was a partially shown corpse in episode 2’s Enclave scene that looked like a super mutant, but the show didn’t linger on it.

Reserving the introduction of the super mutant for an existing character like Thaddeus would indicate that the series intends to make its debut a massive moment for the show. As for how it’ll impact him physically, it goes without saying that Thaddeus would immediately become a force to be reckoned with. As a hulking powerhouse that can take bullet after bullet, a super mutant is a danger to any survivor in Fallout’s apocalypse. They can be beaten, of course, but aren’t easy to kill. With that in mind, Thaddeus could become a formidable villain in Fallout season 2.