Characters overlooking the landscape with mountains and water
Image via Naughty Dog

Top 10 Best TLoU and The Last of Us 2 Fan Theories

With TLOU 2's remaster releasing, it's the perfect time to look back at the series' best fan theories.

There are plenty of fan theories surrounding The Last of Us and TLoU2. Whether involving the Cordyceps fungal parasite or what really happened to the Fireflies, players have dug into the lore to uncover more about Naughty Dog’s action-adventure game. Here are the best theories.

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Most Interesting Fan Theories About The Last of Use and TLoU2

10. Natural Disasters Accelerated Cordyceps Infections

The buildings in the world of TLoU are in shambles, considering what we see in the beginning scenes of the game. One theory is that natural disasters such as earthquakes and tsunamis accelerated their decline, especially in major metropolitan areas. The same natural disasters could have helped accelerate the spread of the Cordyceps spores to the point that the infection couldn’t be contained.

It wouldn’t be extreme to think that this happened, either. We’ve seen real-life natural disasters set up conditions perfect for spreading infections. The disasters don’t cause the infection, but they displace large amounts of people and damage important infrastructure, creating an ideal setting for infections to spread quickly.

9. Joel is Immune

Joel talking to Ellie inside a house
Image via Naughty Dog

There are moments in TLoU2 where Joel mentions others may be immune to the Cordyceps infection. While this could simply be his way of keeping the truth from Ellie just a bit longer, it could be him trying to tell Ellie — and us — something.

Joel often gets close to the infected and their corpses. While he wears a mask sometimes, he usually isn’t. Given how often he gets near infected or walks through areas where spores would definitely be in the air, it’s a wonder he never got infected. But then again, other characters find themselves in similar circumstances, so they can’t all be immune, can they?

8. The Seraphites are a Branch of the Fireflies

The Seraphites are extreme religious zealots, meant to show that even the Fireflies and the WLF aren’t that bad. However, the Fireflies and the Seraphittes have an interesting way of communicating that the WLF doesn’t: whistling.

Sure, this could be a coincidence. But the Fireflies’ actions aren’t always as well-intended as they’d have you believe. As such, I’d be willing to bet that some members broke off in the early days and created their own faction. Former Fireflies, like those from Abby’s faction, joined the WLF, and even some WLF put their lives at risk for those in the Seraphites.

7. Ellie’s Mom Was Infected While Pregnant

One theory for Ellie’s immunity is that Anna, her mother, was infected shortly before — or during — Ellie’s birth. Because of this, Ellie’s early exposure to the Cordyceps infection built an immunity to the infection instead of killing her. Since we only know that Ellie’s mom died around the time of her birth, it’s not impossible for this to be the case.

Interestingly, Ellie’s mom was bitten and infected in this same scenario in the TLoU HBO show. While I suspect the games trump the TV show in this regard, it seems the showrunners and developers who helped create it are at least aware of this fan theory. Or originally intended the sequence as part of Ellie’s video game backstory.

6. Ellie Gets a Happy Ending

Plenty of players believe that Ellie has nothing left at the end of TLOU2. The farm she goes to is abandoned. However, some small details point to the opposite. Ellie isn’t surprised or concerned seeing the state of the farm. Her wounds have mostly healed, and she doesn’t have her weapons. It seems like she’s just visiting or taking items from the farm instead of returning there permanently, meaning her ending could be happier than we suspect.

5. Ellie Killed Riley

Ellie and Riley make faces while taking photos
Image via Naughty Dog

While heavily implied, Riley’s official cause of death remains unconfirmed. We know Ellie and Riley were together, and both were bitten. We also know Riley dies before TLOU, and we see her in the Left Behind flashback. But we don’t see her actual death. However, it’s possible that Ellie had to kill Riley to spare her from a gruesome fate, roaming the world without any sense of her former self. In fact, this would probably be the most merciful end that Ellie could’ve given her. And considering their story, it makes the most sense.

4. The Fireflies Never Wanted a Cure

Did the Fireflies really want a cure for the Cordyceps infection? Maybe not. keeping Ellie alive and studying her immunity would have been a more logical solution than killing her. However, the Fireflies’ first course is to surgically harvest her brain. This usually isn’t how vaccines are produced in real-life, and the Fireflies should have been more interested in her immune system than her brain.

Marlene didn’t want to operate on Ellie initially but was ultimately convinced by Jerry Anderson, the doctor who operated on Ellie — and who just happened to be Abby’s father. There’s a meta-thread about choice in their conversation in TLoU2, but handling the situation as they did adds suspicion on the group. Abby’s father wanted a cure, but what did Marlene want? To really save Ellie? Or …

3. The Fireflies Wanted Control of the Cure

Marlene holds her hands up in surrender
Image via Naughty Dog

Alternatively, the Fireflies may have wanted a cure, but only to monopolize it, using it as a weapon of power over other groups. By killing Ellie, the Fireflies take away the chance for other groups to study her and build a vaccine of their own. It wouldn’t be far-fetched to believe the Fireflies intended to make a cure but wanted to ensure they were the only ones able to do so.

2. Abby is Immune

If you listen to conversations among the NPCs in Santa Barbara, one mentions Abby has the Cordyceps infection. However, Abby clearly hasn’t turned when we see her. Could she be immune? Maybe. Another interesting bit of information comes when Abby talks to Jerry in the hospital flashback and says she would’ve wanted him to do the surgery if it was her. It’s possible that she was an alternative candidate, but didn’t realize it — or was never told that she was infected and immune.

Perhaps TLoU2 would have been more tragic had that been the case, making Ellie and Abby more narratively similar than they already are. Especially since Joel killed the doctor to save Ellie, whereas Abby would’ve volunteered herself, making her father kill her instead.

1. Ellie Has a Different Strain of Cordyceps

MatPat on Game Theory lays this TLoU fan theory out really well. When see Ellie’s medical test results from her childhood, we see she has a suppressed immune system. The idea is that her infection was a strain of Cordyceps that weakened her immunity and prevented her from turning. Which is the opposite of what the primary strain does in TLOU. It increases immune system activity. It doesn’t decrease it.

Ellie likely has Tolypocladium Inflatum, a strain of fungus used to produce Cyclosporine, an immunosuppressant and anti-fungal medicine. This would mean she tests positive as infected if the tests aren’t specific enough to the primary strain. But she wouldn’t turn if she contracted the primary strain because the Tolypocladium Inflatum strain fills her with antibodies. We see it with common ailments in real-life every day..

Those are the top 10 best The Last of Us and The Last of Us Part 2 fan theories. Although both games bring a memorable and emotional story, looking deeper into the content gives us a lot of theories to speculate. But from here, head over to our TLOU2 guides hub in preparation for the remaster, and take a look at what we thought about the TLOU2 remaster.

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Melissa Sarnowski
Melissa Sarnowski has been working as a gaming writer professionally for two years, having been at GameSkinny for over a year now as a horror beat writer. She has an English degree from University of Wisconsin - Madison. While she focuses on all things horror, she also enjoys cozy games, MMOs like FFXIV and WoW, and any and everything in between.