Can someone give me a summary of everything that happened since they went to the basement and explain it like I'm a 5 year old. I feel so fucking lost...
They uncovered many truths about the world, the titans, and their situation. Then they left the walls and made it out to the shore. Since then there has been a timeskip of 4 years.
The central conflict has been revealed to be a struggle between two nations/peoples that has been off and on for some time. Most of the people within the walls belong to a people called the Eldians, who once held the power of all the special titans(there are 9 of them). An Eldian from over 1800 years ago named Ymir Fritz was the first to gain the power of the titans. She used it to establish a society and before she died she split the power into 9 successors(the 9 titan shifting powers were handed down).
On the other side of the conflict there are the Marleys, who were the dominant nation before Ymir Fritz found the power of the titans. After the Eldians gained this power they decimated and subjugated the Marleys for many centuries.
Eventually an Eldian king who gained the power of the Founding Titan moved to an island called Paradis(where the story within the walls takes place), created massive walls made of colossal titans, and erased everyone's memory with his power. Around this time the Marley were able to grab the power of 7 of the titan forms for themselves due to the absence of the founding titan's abilities to maintain Eldia's control. This struggle was the Great Titan War and it turned the tides of power in Marley's favor. The Eldians on Paradis were protected however due to their massive army of titans hidden within the walls(basically a deterrence to unleash upon the world in the event they are attacked by Marley).
Marley eventually began to exile people to Paradis and use titan spinal fluid injections to turn them into titans so to keep the Eldians within the walls contained. Eventually after Grisha(Eren's father) is betrayed by his own son Zeke(now the Beast Titan) he also gets exiled, but just before he is to be turned into a mindless titan an undercover Eldian operative who has the power of the Attack Titan(the titan form Eren now uses) saves him by killing all the Marley soldiers. He gives Grisha the power of the Attack Titan because his life is almost over(titan shifters only have 13 years to live after they obtain a titan form). Grisha starts a family and has a son within the walls, eventually injects Eren with titan serum after the death of Eren's mother, and has mindless titan Eren eat him to obtain the power of the Attack Titan. The Colossal Titan, Armored Titan, Female Titan, and eventually the Beast Titan during this time have begun an operation to infiltrate the walls and bring the final titan forms off the island(of course this fails big time and results in Marley actually losing some of their titan powers, Female and Colossal).
After the timeskip we see Marley struggling to maintain warfare superiority in a world where titan power is finally becoming irrelevant in the face of technological advances. They've lost titan forms and have lost the edge in battle against new anti-titan weaponry. All the while word from Paradis island has been silent for years...
I'm sure I've missed something important but that's the gist of it(if anyone else could chime in to add or correct something here that would be appreciated), a lot of backstory and the answers to most of the series big questions have happened since the basement reveal.
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