Firstly, I should say this article will feature some spoilers from the manga which have not been revealed to fans of the anime. These spoilers are minor and will not reveal any major plot points of the story. So if you wish to keep it all a secret, I suggest not scrolling any further, if you do continue, you only have yourself to blame!
1. How old is the franchise?
Many fans met the series in 2013 when the anime went international, but those fans, while all very loyal to the franchise, may not be aware they joined the fandom seven years after its initial inception! Yes, Attack on Titan began nearly ten years ago!
Hajime Isayama, the writer and artist behind the franchise, started it off back in 2006 with a one-shot manga. The manga was a 65-page story which earned Isayama the Magazine Grand Prix's 'Fine Work' Award at the young age of 19. Three years after the one-shot manga was released, Isayama's editor suggested a return to the manga, creating the ongoing series we have today.
2. Eren was meant to know he was a Titan Shifter
In the original concept for the series, Eren was intended to know he was a Titan Shifter. This was revealed by Isayama's editor, claiming this alteration to the character drastically changed how he would have been portrayed in the manga. The current current storyline if Eren discovering his Titan ability made the creator feel he had nailed the character perfectly, as he is seen dealing with setback after setback. This was even dubbed "more Eren like" by the creator.
3. The Avengers have fought the Titans
Now you may be thinking I have had to many drinks writing this article and have gotten confused — but you would be wrong. Marvel are no idiots when it comes to how to access popular media, and so teamed up with Attack on Titan creator Hajimo Isayama.
Spiderman and Captain America were among the Marvel heroes to appear in the special of the manga. Titled Attack on Avengers, the eight-page special shows fans what would happen if the Titans invaded the Marvel universe. You have to admit, you want to see that special!
4. A talking Titan exists
The Beast Titan is yet to appear in the anime, but will debut near the beginning of Season 2. He does appear in Season 1, as it ended on Chapter 33 of the manga, and he debuts in Chapter 35. He is a mysterious Titan that resembles cryptids such as Bigfoot, more than a man like the other Titans. Even more mysterious, he can talk. With this ability, he clearly demonstrates an intelligence — and can even command other Titans. He also appears to have had little, if any, contact with the humans behind the walls, as he is intrigued by the 3D maneuvering gear.
5. Sasha was meant to die in Volume 9
Sasha Blouse was originally intended to be killed off in Volume 9 of the manga. During the initial planning for Volume 9, the character had a chapter (36) focused on her, which was meant to end with her apparent death. However this was changed as Isayama was apprehensive about killing her off.
The editor behind the series even cried in the bathroom after reading the original storyboard, which helped convince Isayama to keep Sasha around. The editor later stated that Sasha shouldn't be killed at this point, but at the same time said there would be a more appropriate moment on the horizon for that to happen. So Sasha may not be completely safe, as it seems they do still intend to have her meet her maker one day.
6. The Titans were based off of famous Martial Artists
The Rogue, Colossal, Armored, Female and Dancing (yet to appear in the anime) Titans all share very muscular and athletic structures to their bodies. This makes them always ready to engage in action. The reason for this is because Isayama used the physiques of famous fighters when designing them. He has confirmed Eren Yearger's Titan form was modeled after the mixed martial artist Yushin Okami, who competed in organizations such as the UFC and Pride FC.
The other confirmed inspiration is the design for the Armored Titan, based on the appearance of the professional wrestler and mixed martial artist Brock Lesnar — the resemblance is undeniable. It is also fitting for the all-powerful mighty Titans to be based off of world-class fighter, whose main intent is to destroy those they face in a fight.
7. Is Zoë Hange male or female?
While Zoë is depicted as female in the anime and is portrayed by the actress Satomi Ishihara in the live-action movies, the character's gender has never been revealed in the manga. Isayama has even stated he does not wish to reveal the characters gender for a couple of reasons. The first being to leave it open for the fans to decide for themselves. The second is because he does not see their gender identification as relevant to the story itself. He even asked Kodansha USA, who are the publishers for the English translated Attack on Titan, to not use gender pronouns when referring to the character.
8. The live-action movies lied!
The live-action movies told fans a lot of lies the deviated from the manga and the anime. Most notable is that of some of the characters. Many characters are missing and replaced with others. Events also massively deviated from the source material. This was done to prevent massive spoilers to fans of the franchise.
The one part you can forgive them for lying to us about, was when they revealed the identities of the Titan Shifters of the Colossal and Armored Titans. I will not state their true identities, so to not spoil that for fans, but the two characters in the movies are not the true Colossal and Armored Titans from the manga and anime.
9. The big confusion on Levi
Levi is a fan-favorite of the franchise, but there are many mysteries behind the character. The first being his age. His age has never been stated and Isayama has simply said that "he is older than 30," continuing on to say he is much older than he appears. The other will come as a shock to many, but the question is does Levi like women or men? When Isayama was asked what type of woman Levi is attracted to, the creator simply replied with "who says he likes women?"
Needless to say this opened up all new questions, but Isayama has stated Levi is attracted to tall people.
10. The biggest mystery is not the Titans
The Titans themselves are not the biggest mystery in the franchise. All fans had the biggest mystery revealed to them, but many will have missed it completely. During episodes, viewers encounters flashes of information, building the backstory, mid-way through the episode. In the final episode, a flash of information was given to fans that went unnoticed, and that was a story behind the walls themselves. The story itself went as follows:
In the year 784 on a blistering hot night, a miner decided to dig under Wall Sina in hopes of living a better life on the other side. No matter how far he dug, the wall never seemed to end. Eventually, he dug so deep that he ran into a layer of bedrock made of the same material as the wall.
With this information, the Titans being within the walls is the last question fans should be asking. If the Wall Cult in the franchise is correct, the three walls of Rose, Maria and Sheena may have indeed been sent by God to protect the last of mankind.