Back when Reiner was with Bertholdt and Annie on Paradis, a man they met prefaced his eventual suicide-by-hanging by telling them a story. The three wondered if the man did so seeking forgiveness—which Annie felt they had no right to give after losing Marcel—or merely wanted to be judged.
Now in the present day, face-to-face with Eren Yeager for the first time in four years, it’s Reiner who wants to be judged, and as someone who witnessed his crimes firsthand in Paradis—not the propaganda Marley peddles—Eren is uniquely suited to do so.
Still, as he urges Reiner to sit down and listen to Tybur’s speech with him, he also insists Falco stay put and listen, both to the speech and to his and Reiner’s concurrent chat. Meanwhile, Porco and Pieck are told to accompany an escort for an undisclosed matter.
Tybur really went all out with the theatrical production, as his speech begins with the story the entirety of the assembled crowd already knows: how the Eldians conquered the world a hundred years ago and then turned on their own people, and how Helos and the Tyburs fought together to free the world of the Eldian hegemony.
Porco and Pieck’s escort is a non-Eldian and doesn’t wish to speak with them en route, but Pieck runs into other non-Eldians who are members of the Panzer division, i.e. soldiers whose lives depend on the Cart Titan over all other groups and thus have a soft spot in their heart for her, even though she’s an Eldian.
Pieck can’t help but think she’s seen the anti-Eldian escort before—perhaps on Paradis?—but she and Porco are led into a house and fall down a trap door into a narrow well in which they cannot transform. Clearly someone wanted them out of the way…but who?
Willy’s speech takes a sudden turn when he reveals that the story of Helps and Tybur saving Marley was nothing but a lie crafted by the Eldian King Fritz, whose plan was to flee to Paradis with as many Titans as possible and stay there, neither attacking nor being attacked by any force. We learn the tripartite walls themselves are composed of countless Colossal Titans and built with the power of the Founding Titan.
Fritz intended to fully enforce the renouncement of war with those walls and never emerge from them. We learned that he inspired the generations that came after to follow suit. But then Eren came into possession of the Founding Titan, and Fritz’s dynasty fell (when Historia rose to power). Thus even though the King had saved Marley by allowing himself to be their most hated enemy, that King’s legacy can no longer be relied on.
The Founding Titan has the ability to convert the walls back into an army of Colossal Titans who would then go on to literally trample the world. If Eren didn’t know this before, he knows it now. As his leg regenerates Falco realizes he was duped into delivering mail to Eren’s allies—who I’m guessing trapped Porco and Pieck in the well.
As they listen to Tybur, Eren asks Reiner why the walls were breached and why his mom was eaten, and Reiner, nearly mad by now with grief, replies that it was because he fucked up. The others were willing to abort the mission when Marcel died, but Reiner wanted them to press on. He doesn’t want to be forgiven for what ended up happening, he wants to be judged and executed by Eren, one of his first victims.
But Eren isn’t here to judge Reiner, any more than he’s here to judge Falco, or Porco and Pieck, or Colt, Gabi, Zofia, or Udo. They were all just kids, after all, told just like he and his friends were told that The Other Side were evil demons, when in reality both sides were mostly just regular people. Those responsible for the atrocities in Marley and elsewhere were long gone, though they were still ruled by their descendants.
So no, Eren won’t blame or judge brainwashed kids past or present for the state of his family, people, or homeland. What he will do is put the blame squarely where it belongs: on Willy Tybur, who seems to successfully unite his diverse audience into joining forces to defeat the demons across the sea once and for all. But his big shining moment is stolen by Eren, who transforms into a Titan and bursts out of the building nearest the stage.
A new war has been declared, and it seems that Tybur specifically chose the Internment Zone as its first battlefield, luring leaders from all over the world there in order to witness the ensuing carnage the Titans can cause, perhaps hoping they’ll return and sway their people into joining his cause. In seeking judgment of Tybur, Eren may have played right into his hands…