Attack On Titan Fan Theories

In the Japanese anime, as well as the English dub, the narrator of Attack on Titan is voiced by the same voice actor as Armin Arlert. Marina Inoue and Josh Grelle voice both characters, respectively, which has caused a stir in the fandom, bringing up speculations that Armin may be the narrator of the series.

"Maybe Armin is writing everything for us to read several years later or for a history book," went the prime point in Sookey5's Wiki post pointing out this theory. SheepyBoo also speculates the narration comes from an older Armin, and that the narrator is, "actually Armin, but when he grows up." It certainly feels plausible. 

So Titans are always frantically eating humans, even though they have no means of digesting them. What's up with that?  Well, according to -V0lD on Reddit, it's actually the "general speculation" of the entire Attack on Titan subreddit that Titans subconsciously know eating a Titan shifter will revert them back to human form. Therefore, they eat every person in the hopes they'll turn back, even though they don't seem outwardly to have any real drive or motivation.

FangedFish on Reddit made a post claiming the fearsome giants are actually trying to hold onto humanity, going from person to person desperately trying to eat a shifter because, "subconsciously they want to become human again."

Annie has a lot of secrets to reveal and a much, much deeper story developing for her. Well, once she gets out of her crystal cocoon. According to a theory posted by Eobard95, Annie only has a set time left to live, and being completely crystallized might be slowing down her death. If so, it's in her best interest to save her strength for a massive final fight, which will most likely be against Marley.

If the Survey Corps can convince Annie to join them, even out of anger or a desire for revenge against the people who put her in this situation, then it would prove to be a grand comeback for her.

The walls guarding humanity against the onslaught of Titans are actually composed of Titans, this much we know for sure. But what will their fate be? Snkconspiracytheories thinks these Titans are going to be used by Eren as the ultimate weapon of war.

With thousands of Titans residing inside of the walls, they will inevitably be, "The strongest weapon to end the war against Marley."

In a very well thought-out and scientific theory about the physical composition of the Titans, fans have theorized that Titans are actually made of yeast. Not only does highly fertile yeast collect around the outskirts of Wall Sina, where there are a ton of Titans, fans have pointed out numerous connections between yeast and the behavior of the giant, bumbling beasts.

Tumblr user danilovesanimenel reposted the theory from a Ymir page, pointing out their personally discovered yeast facts. They show that, scientifically, "yeast produces a large amount of gas and heat, much like the bodies of Titans," and that "UV rays increase yeast productivity," which "means that if a large component of a Titan’s biology is yeast, then the reason for their sluggishness during the night is that the sun is their energy." Frankly, the whole argument is pretty compelling. 

Eren, Armin, and Mikasa have been together since they were children. Eren and Armin are driven by a desire to kill Titans and save humanity, while Mikasa is more concerned about just Eren. Nylla Camphry predicts that Eren will die in a grand sacrificial way to save mankind, in line with his personality and drive. She also predicts that Eren will have to eat other humans to gain Titan powers, and that it may even come to the point where Eren must eat Armin.

Nylla Camphry goes on to state that Mikasa will be the only survivor of the three childhood friends, as it would tragically suit her character of not wanting to be alone.