Here's a breakdown of everything revealed in Attack On Titan courtesy of Eren's basement, including the Eldians, Marley and the history of the Titans. From the very beginning of Attack On Titan, Eren's basement key has been a major point of mystery. What secrets had Eren's father hidden beneath the family home that would supposedly explain everything? Those answers finally arrived at the end of Attack On Titan season 3, after the Survey Corps. fought a desperate battle to regain control of Wall Maria, the enclosure where the ruins of Eren's house still sat unexplored.
Many fans feared that whatever the basement contained couldn't possibly live up to the hype and expectation placed upon it but, fortunately, these worries were unfounded. After finally making his way into the basement and locating a secret compartment in his father's old desk, Eren discovered a series of journals and a photograph that essentially revealed the entire truth and history of Attack On Titan's fictional world, answering almost all of the story's major questions and mysteries ahead of Attack On Titan season 4.
Attack On Titan's basement reveal was a huge info-dump, and one that fundamentally altered the landscape of the franchise. As such, there's plenty for fans to wrap their heads around. Here's a breakdown of everything confirmed by Grisha's notes in Attack On Titan season 3, with some of the information complimented by Eren's own Titan memories.
The Origin Of The Titans
Attack On Titan's story begins almost 2000 years prior to the first episode with a young girl called Ymir Fritz. Depending on whom you believe, Ymir is the first person to gain the power of the Titans by either making a deal with the devil or touching the source of all life. In either case, Ymir becomes the original Titan, possessing the power of all nine Titan-shifters from the present-day timeline. Ymir developed a God-like following and, following her death, the power of the Titans was split among nine of her people.
Thanks to "the Curse of Ymir," a Titan-shifter will only live for 13 years after acquiring the power, at which point (or before, should the holder be killed), their Titan will pass into the next Eldian child to be born. Only Eldians, Subjects of Ymir, can become Titans and only Ymir's direct lineage of royal descendants can use the powers of the Founding Titan, or the Coordinate.
The War Between Eldia And Marley In Attack On Titan
With their newfound abilities, the Subjects of Ymir created their own nation of Eldia and set about building an Empire that covered a large part of the planet - an allegory to the Roman Empire of real-world history. Much like the Romans, the Eldians viewed themselves as pioneers, using their Titan powers to help develop the lands they ruled over, constructing entire cities and overrunning their opponents with unmatched power. However, those not of Eldian descent viewed the Titan-powered nation as a race of invading conquerors, who used their transformations to slaughter countless innocents in the name of the Eldian Empire and then treated the natives as slaves. It's not yet clear which account is accurate, although the truth is most likely a mixture of both viewpoints.
Before Ymir Fritz first inherited the power of the Titans, Marley was the world's most influential nation. Not taking too kindly to being usurped by a bunch of naked giants, Marley and Eldia eventually found themselves at war, although nothing could overcome the ferocity of Eldia's nine Titans. Fortunately for Marley, those nine Titan-shifters - who had since become famous noble Eldian houses - were beginning to bicker and jostle for power among themselves.
Seizing this opportunity, Marley stoked the embers of discontent among the Eldian elite and found an opening within the division. Gradually, Marley acquired seven of the nine Titans for themselves, depriving Eldia of their biggest military asset and finally beginning their return to prominence.
The Formation Of The Walls 100 Years Before Attack On Titan Begins
As war rumbled on, the Eldian king of the time, Karl Fritz, exiled himself to the remote Paradis Island, and with defeat looking increasingly inevitable, other Eldians began flocking to join him. With Marley's victory imminent, Karl Fritz made a proclamation to bring the conflict to an end. He and the Eldians who had reached Paradis would confine themselves within three giant walls constructed entirely of Titans and, using his power as the Founding Titan, Fritz would make an oath that would bound both him and his successors to never trigger another war or use their powers to fight back. In exchange, Marley would leave Paradis Island in peace, with the mass of Titans hidden in the walls acting as a further deterrent. To prevent public outcry and future battles, King Fritz wiped the memories of everyone living behind the walls.
The truce was made official, but many Eldians failed to reach to Paradis Island and were stuck on the Marley-controlled mainland. These citizens were subjugated and treated as second-class citizens, directly paralleling Nazi treatment of the Jews during World War II. However, a select few Eldians were promised a better life in exchange for taking on one of Marley's seven Titans and fighting as part of their military.
Should an Eldian commit a crime or violate the rules placed upon them, they would be taken to Paradis Island and injected with a serum that turned them into a mindless Titan. These creatures were then left to roam the land outside of the three walls and these transformed humans are the Titans seen and fought against throughout most of Attack On Titan.
This peace continued for a century but, as Grisha explains, Marley's continued military expeditions around the world had greatly drained their resources. Paradis Island sits on a huge reserve of valuable natural resources, so the Marleyan government decided to renege on their truce with the Eldians and send a team inside the walls with the ultimate aim of bringing down the last Eldian stronghold. This team consised of Annie, Reiner and Bertholt, and directly leads to the events seen in the very first episode.
Grisha Jaeger's Story In Attack On Titan
As well as gaining an insight into the background of the Titans and the layout of the outside world, Attack On Titan's basement reveal also chronicles Grisha Jaeger's personal journey, having previously been a man of mystery. Grisha was part of an Eldian family living under Marleyan rule and, after violating the strict restrictions on Eldian movement, Grisha's sister was mercilessly killed by a Marleyan guard. This pivotal moment eventually inspired Grisha to join the Eldian Restoration movement, and he would go on to marry a descendant of the Fritz family and have a child named Zeke.
Grisha attempted to raise Zeke as Eldia's final hope, but the young boy sold his parents out and the entire rebellion was discovered and quashed. The members of the Eldian resistance are taken to Paradis Island and, one by one, transformed into Titans. However, Grisha is saved when one of the Marleyan guards carrying out the execution reveals himself to be the secret leader of the Eldian Restoration movement, who had infiltrated the authorities of Marley in order to pass on vital intelligence. This man, named as Eren Kruger, also holds one of the two Titans that elude Marley, the Attack Titan. Since Kruger is coming to the end of his 13-year term, he passes the Titan onto Grisha and sends him towards the walls, hoping he can finally bring freedom to the Eldians.
In his notes, Grisha reveals how he planned to infiltrate the walls, find King Fritz and retrieve the Founding Titan for himself to use as a weapon against Marley.
Attack On Titan season 4 premieres in 2020.