13 Popular 'Attack on Titan' Fan Theories That Eventually Got Debunked

Before Eren decided to try and destroy all life outside of Paradis using the Rumbling, fans were theorizing about how the problems of the series could be solved. 

u/CuriouslyProgrammed had an interesting take. One Titan shifter will eat all the others, and then seal themselves in a crystal. This would require signficantly fewer casualties than Eren's plan, although it would create a sad situation in which a few protagonists would have to sacrifice themselves. Clearly, this wasn't the option Eren went with.

Initially cooked up by u/real_life_corgi, the Time Loop Theory is an interesting idea that could be its own series - but it's not what ended up happening in AoT. 

Here's a quick run-down: In the 700s, scientists create the Titan virus out of the remnants of Ymir. The government weaponizes the virus and creates a range of Titan varieties to shore up their military might. They lose the vaccine, and Titans run rampant. The secrets of the vaccine are contained within Eren's dad's basement, but they are destroyed. Eren writes a letter to the future, which begins "To you, 2,000 years from now," in the hopes that the future world will be able to go back in time and fix things.

The twist is that Eren was actually sent from the year 2800 by his mother Mikasa. These events occur across multiple time loops, each one ending with the destruction of humanity. 

What if the world of Attack on Titan that we're presented with isn't the only world that's supposed to exist? According to the Multiverse Theory, which was painstakingly created by u/emmyeggo, there could be multiple universes within the AoT world.

 The theory is long and complex, so to get a feel for it, you'll need to check out the original post. The quick and dirty version is that the AoT universe is not the original universe, but one which Eren created to deal with his boredom. 

The manga features a series of fake chapters called Attack on School Castes, which sees the characters in a modern-day school setting. In that setting, Eren dreams about a zombie apocalypse and then gets upset that there wasn't any exciting danger like that in his own life. He considered creating that danger. 

How does this link to the main story? Well, a panel from School Castes appears in Eren's memories in the manga itself. Also, Isayama said in an interview that he liked the AU because, he said, "If possible, I want to draw something that is linked to the original manga’s universe. That’s how I’m approaching it now." 

The manga has ended without definitively revealing a multiverse, which means the theory remains unproven. But who knows, maybe a sequel will come along and shake things up. 

At first, Reiner and Bertholdt didn't describe their hometown in detail. Before fans knew about Marley and the Eldian internment zones, they came up with other ideas.

 One common theory was that the two of them came from a village full of Titan shifters. This implies hundreds or even thousands of Titan shifters, which could have been exciting or overwhelming depending on how it was executed. 

Eren Kruger was the person who started the Eldian Restorationist movement, as well as the person who initially held the power of the Attack Titan. He was a majorly important figure in Grisha Jaeger's life, which is why he named his second son after him. Some fans thought Eren Kruger was Eren Jaeger - either in reincarnated form or via time travel. The main reason for this was that Kruger talked to Grisha about Mikasa and Armin, two people who hadn't even been born yet.

 This was explained by the fact that the Attack Titan can see the future memories of those who will inherit it. That eliminated most support for the theory. 

While Attack on Titan is certainly inspired by the real world, it doesn't take place in the real world. However, many fans thought AoT was set in a post-apocalyptic version of Earth.

 One of the biggest reasons was Mikasa. She was referred to as "oriental," which is a real term that was once used to describe Asian people but is now considered offensive. Some translations even called Mikasa Japanese, which is a real-world nationality. 

It turns out that Orient is the fictional name of a continent that is loosely inspired by Asia, which is why Mikasa was called that. But she's from a nation called Hizuru, which is based in Japan but isn't Japan itself. Japan doesn't exist in this world, and neither do any other real-world nations. 

This one hasn't been disproven since we never did get to learn exactly what Titans are made of, but since the series ended without a firm declaration in its favor, it's close enough to deserve a spot on this list. Despite not being canon, it's so well thought-out that we kind of wish it was.

 In areas with high Titan populations, unusual strains of yeasts have been found. Yeast produces massive amounts of heat and gas and can cause the material around it to expand. When a person turns into a Titan, they expand. UV rays can increase yeast activity, which could be the reason that Titans require sunlight to function. But why would a person be able to turn into a Titan if the whole thing is powered by yeast? There are proteins in human blood that can bind to yeast. Some yeasts can cause infections in humans. 

At this point, fans know that the Ninth Titan is the War Hammer Titan. Before that was revealed, some thought it might be not just one Titan, but a power possessed by several people - specifically, the members of the Ackerman clan.

 The Ackerman clan was originally created via Titan science to protect the Eldian king. As a result, they have several unique abilities. When they rebelled against the king, they were nearly wiped out, leaving only a few surviving members. 

Some people thought their abilities would culminate into what amounts to a Titan power. Considering how awesome Levi is, it's too bad he didn't get this particular spotlight. 

For a long time, nobody knew how the Titans had been created. While we know now that they began with Ymir Fritz and the Founding Titan, fans had ideas about it in the meantime. One popular theory was that Titans were created through scientific experimentation. Because he was seen turning Eren into a Titan using a mysterious liquid, some thought Grisha was the one behind all of Titan-kind.

This seemed a little implausible due to Grisha's age, but a few reveals made it seem possible again. Ymir was once a mindless Titan, and she spent 60 years wandering aimlessly before becoming a Titan shifter with a human form that looked like the teenager she'd been when she was initially transformed. Grisha had also been a Titan once, so he could have been much older than initially assumed. 

But while that detail helped the theory a little, it still turned out not to be true. 

Zeke's identity is clear now, but when he was first introduced, fans didn't know much about him. Some speculated that he could have been Erwin Smith's father. 

When Erwin was a young boy, his father "disappeared" after Erwin inadvertently revealed that his father knew about the brainwashing that had been going on within the walls. While his demise was heavily implied, some believe he actually survived and went on to pursue his theories further. 

Zeke is only 25, but he looks significantly older - old enough that it's not hard to imagine him being in his 60s, which is about how old Erwin's dad would have had to be in the modern day.

The Ackerman clan's abilities are the result of scientific experiments designed to make them the perfect protectorates of the Eldian king. Some theorized that these genetic modifications made it impossible for them to take down Titan shifters. This might explain why Mikasa failed to take down Reiner and Bertholdt and why Levi couldn't deal with Reiner.

 This was disproven when Levi helped feed Bertholdt to Armin in order to transfer the Colossal Titan and save his life. But some thought this didn't count as proof since he wasn't directly responsible for Bertholdt's demise. But the theory was dramatically and definitively disproven at the end of the manga when Mikasa ends Eren's life to stop him from destroying the world. 

The Smiling Titan appeared at the very beginning of the series, and their true identity wasn't revealed until close to the end. That left a lot of room for speculation. One of the most popular guesses was Armin.

 Why Armin? First of all, they looked somewhat similar in terms of hairstyle. Second, Armin didn't appear for a few chapters while the Smiling Titan was active. Third, he appeared in one panel with a starburst background that could have indicated transformation. 

The theory was disproven when Armin was depicted in the same place as the Smiling Titan and disproven once again when it was revealed to be Dina Fritz. 

When Marco lost his life during the Battle of Trost, it was one of the most upsetting parts of the early seasons. Some people thought it didn't actually happen - instead, they thought he'd become a Titan shifter. Fans had differing opinions on which Titan he had become, though many thought he was the hooded figure who attacked Gunther. This was Annie, but some thought it was Annie's accomplice, Marco. The torn-up body wasn't Marco's, but that of another soldier who looked similar. 

This theory was put to bed once Marco's demise was show in full.