Engaged in a centuries-long conflict that began as a battle between rival tribes which swiftly escalated into an all out war between empires, hostilities between the nations of Eldia and Marley have been responsible for most of the tragedies that have befallen the main cast of Attack on Titan. Long before the fall of Wall Maria at the start of the series to the assault on Liberio, and finally, the horrors of the Rumbling, the two nations had been at odds for virtually all of recorded history, perpetrating atrocities against one another that fueled a generational cycle of hatred. In the end, the unwitting protagonists of Attack on Titan found themselves embroiled in this conflict simply by virtue of their birth, with little idea of whether their side was in the right or not.
While the Eldians were the ones being persecuted at the start of the story, with the islanders on Paradis serving as the object of the world's collective hatred, spurred on by Marleyan propaganda at its head, they were once the oppressors who held dominion over large parts of the known world for centuries. A key factor in the supremacy of the former Eldian Empire was the Power of the Titans. For nearly two millennia after Ymir Fritz became the first Founding Titan and turned the tide of the war in Eldia's favor, Marley suffered due to their inability to combat the Titans with their technology, which had not reached a sufficient level of advancement at that stage. However, all this changed a century before the start of the story with the migration of the Fritz family to Paradis island and the creation of the Walls. There is a lot to unwrap when it comes to this age-old geopolitical discord, particularly in light of the contradictory accounts espoused by the Eldian and Marleyan sides. Hence, in this case, it is best to start at the very beginning to trace the origin of this conflict at its very root.
The Dawn Of The Age Of Titans
Around 2,000 years before the start of Attack on Titan's main storyline, Ymir was a slave who had been captured by the then tribe of Eldia, led by its tyrannical ruler named Fritz. This primitive group often pillaged neighboring settlements and civilizations, resorting to barbaric acts of discipline in order to stamp their authority in the faces of those they had subjugated by force. Ymir, who had been condemned to death by the tribe's ruler for opening up a pen that set the settlement's domesticated pigs free, stumbled upon a massive tree in an attempt to flee from the wrath of her captors. After falling into a pool of liquid inside the shelter of the tree, she inadvertently came into contact with the source of all living matter, which bound itself to her spine and turned her into the first Titan. Taking note of the immense power she now wielded, King Fritz commanded Ymir to lay waste to enemy nations, and the young impressionable girl heeded his every order with no resistance.
Ymir's power cleared the path for the development of Eldian civilization, ushering in an era where Titan power reigned supreme. Eldia grew to become a dominant global power, forcing all its adversaries to cower in fear of its wrath, as the Subjects of Ymir were the only race who could transform into Titans. With the Founding Titan, Ymir is said to have built bridges, roads, cities, and other infrastructure, as per the Eldian version of the story. As a reward, in his eyes, King Fritz took Ymir as his wife, and she bore him three daughters — Maria, Rose, and Sheena. Just 13 years after acquiring the Founder, Ymir was slain while attempting to defend her king against a Marleyan assassin. Seeking to ensure that Ymir's power would endure, King Fritz ordered his daughters to consume her remains, laying the seeds for the tradition of inheriting Titans. No Titan could hold on to their power for more than 13 years, as none would ever be as powerful as Ymir herself.
A Fierce Battle For Supremacy
Over time, the Eldian Empire waged war against innumerable nations and settlements, slaughtering and pillaging in a bid to gain more territory and power. At this time, being a Subject of Ymir was considered a mark of high social status worldwide, owing to the empire's complete control over the continental mainland along with the territory of Paradis Island. The Eldian Empire's dark history of war, slavery, and savagery is said to have wiped out countless cultures over its lifetime, with the actual number of casualties estimated to be more than twice the global population at the start of Attack on Titan's storyline. Marley and its citizens were among the worst affected by Eldian warmongering, with existing records narrating how entire cities were wiped out by Titans in less than a single day.
Most of Nine Titans had been distributed among Eldian noble families over the centuries, with all having to swear fealty to the Fritz King who would be in possession of the Founder. Eventually, once all external threats had been extinguished, a period of infighting between the eight noble houses began, where the Fritz ruler was forced to maintain order with the authority of the Founding Titan. Just over a century before the start of the story, Karl Fritz, the 145th king, came to possess the power of the Founder. A pacifist who was disgusted by the misdeeds of his ancestors, he believed that Eldia's crimes could not be atoned for, and colluded with the Tybur family and the Marleyans to put an end to the Eldian Empire. Abandoning the internal politics of the empire, Karl Fritz took the Founder and a select group of his subjects to Eldia's territory of Paradis Island, where he built three concentric Walls — named in honor of Ymir's daughters — with Colossal Titans, threatening to unleash them upon the world if any would dare to disturb the new civilization they had created there.
The power vacuum so created by Fritz's withdrawal led to the collapse of the Eldian Empire over the course of the Great Titan War, where the noble houses fought against one another indiscriminately. Over the course of the war, Marley arose from its subjugation and managed to capture seven of the nine Titans, emerging as the dominant power that would replace Eldia after the battles concluded. Additionally, Fritz had also devised a false legend about the Marleyan hero Helos, who fought alongside the Tybur family and Marley. The Eldians who remained on the mainland became second-class citizens who faced constant persecution at the hands of Marleyan authorities, and were segregated from the general populace, being forced to reside in designated internment zones.
All Eyes On Paradis Island
Now, with Marley's ascendancy, the stature of Subjects of Ymir began to plummet all over the world, aided by Marleyan propaganda which slandered the already tainted legacy of the Eldian Empire. To add fuel to the fire, Marley claimed that the Eldian Empire had dabbled in eugenics, and also attributed the Power of the Titans to having originated from Ymir making a deal with a fabricated entity known as the "Devil of All Earth." Despite this, the Marleyan military continued to use Titans in warfare, and even turned their Eldian subjects into Pure Titans, letting them loose upon the battlefield, treating them as little more than weapons, even as their own technology lagged behind the rest of the world. Eldians convicted of crimes against the Marleyans also endured a similar fate, where they were sent to Paradis Island and turned into Pure Titans to forever roam the land beyond the Walls.
Having crushed all resistance against them, Marley began to surpass the Eldian Empire's cruelty, albeit they justified these acts by repeatedly admonishing the Subjects of Ymir for the crimes of the past. In this climate, a small band of Eldians on the mainland began to question Marleyan propaganda, seeking to return Eldia to its former glory. This group, dubbed the Eldian Restorationists, were led by none other than Grisha Yeager, with the aid of spies like the "Owl," later revealed to be Eren Kruger, the holder of the Attack Titan. Sadly, they were also apprehended, convicted and sentenced to become Pure Titans on Paradis, which finally brought Grisha to the shores of the island, setting the main storyline of Attack on Titan in motion. Over the course of this conflict, both sides have committed equally heinous acts, and it is difficult to say who is in the right or the wrong, even when much of the story has been told from the perspective of the Eldians of Paradis.