|Was this really what I needed to do...to save Eldia?! Why...won't you show me everything...?|
|— Grisha Yeager after seeing the memories Eren has given him|
Continuing through Grisha Yeager's memories, Zeke comes to accept that Eren has never been manipulated by their father. However, Eren sends his father memories of the fall of Wall Maria through the Attack Titan, prompting his visit to the Reiss family the night the Wall falls. Though his father hesitates at the idea of killing the entire family, especially the children, Eren goads him into doing it, reminding Grisha of everyone who has died to get him this far.
The connection breaks between Zeke and Eren in the present, and Zeke is shocked that Eren manipulated the stealing of the Founding Titan, which was only possible because Zeke took him into Grisha's memories. However, he realizes that Eren cannot see everything, because he did not know that he would be unable to command the Founder inside the paths, so he commands Ymir to remove the ability for all Subjects of Ymir to reproduce.
Still inside Grisha Yeager's memories, Zeke is surprised that Eren was raised without the same indoctrination he received. Given Eren's freedom to choose, Zeke is puzzled that Eren would betray him and carry out his father's plans when he received the Attack Titan without being told a thing.
However, Eren replies that he has always been this way. The two of them arrive at the memory where Eren killed two of the three robbers who had kidnapped Mikasa Ackerman while they were children, and Zeke is as surprised as Grisha by the bodies. As Grisha scolds Eren as a child, the present day Eren explains that Zeke expected the two of them to be similarly scarred, but Eren fights because that is who he is, and not what his father made him. He is different from Zeke, who Eren sees as a man who can only define himself by his willingness to deny a father who died years ago.
Zeke chooses to express gratitude instead, because Grisha opened his eyes to the dangers of Eldia. He begins to leave, but Eren does not immediately follow, instead watching his childhood self wrap a scarf around Mikasa.
As they go through more memories, Zeke persists in his refusal to give up on Eren. He does not think much of Grisha's writing on the back of the photograph that he eventually stores in a journal in the basement, and the two of them watch the Yeager family as the childhood Eren expresses his desire to join the Survey Corps. The young Eren talks about not wanting to be ignorant of the world outside the Walls and wants to carry on the work of those who sacrificed their lives, so they did not do so in vain. Grisha then offers to show Eren his secret in the basement after he gets home.
But when Grisha leaves, he becomes bothered, seeing a vision of the evacuation of Shiganshina District during the fall of Wall Maria. This prompts him to return to the chapel where he had previously discovered stairs leading underground. He follows them down and finds the members of the Reiss family gathered in the cavern below.
Grisha explains that he is an Eldian, and a Subject of Ymir, who has come from beyond the Walls. He asks the King of the Walls to kill all the Titans attacking the Wall before his family and the other people within the Walls can be eaten. Frieda is initially distressed by his words, but then her expression smoothes as the will of the First King takes over. She refuses to help Grisha, calling this a time of judgment. The rest of mankind is too weak in the face of the power of the Titans, so in order to protect the world, the Eldian people must accept their sins and perish.
Still watching, Zeke believes that he would get along with Frieda, but is aware that the Reiss family will soon be slaughtered. Eren had previously said seeing this memory had made him lose hope in his father, and Zeke asks Eren if that was a lie, but Eren does not reply. He stares intently at Grisha who is becoming increasingly agitated.
Grisha wants to know how this can be atonement when the people are ignorant of their history and had no part in what happened. Frieda agrees that this is not atonement, because they can never replace the lives they took, but they can prevent the taking of future lives outside the Walls. As long as Eldians remain ignorant, they will be the only ones to die.
Sensing something behind him, Grisha just barely turns to see Eren glaring balefully at the Reiss family. Even Zeke notices something is odd with his brother.
Oblivious, Frieda continues her speech and informs Grisha that even if he were to take the Founding Titan from her, he would not be able to use it. Grisha admits he knows this, and shares with her the Attack Titan's own power. It is able to see into the memories of its future inheritors, and through them, it can know the future. Frieda is not aware of this because the vow to renounce war prevents her from using the full power of the Founder.
Grisha tells Frieda that he will take the Founding Titan from her and end the royal bloodline, setting the future that he already knows is going to happen, but his hand shakes as he grips his scalpel to injure himself. It falls from his hand and clatters to the cavern floor. Grisha sobs that he cannot kill children. He is a doctor and he is supposed to save lives.
Zeke is puzzled, because he is aware that the Reiss family died. The past should not have changed.
The Reiss family begins to rally from their hiding places, shouting for Frieda to kill Grisha and protect them, as Eren walks up to his father. Still glaring, he demands that Grisha stand, and asks if he forgot why he had come here in the first place. Eren brings up all the things that Grisha had set aside over the years; revenge for Faye, Dina Fritz, the Eldian Restorationists, Kruger. He repeats what Kruger had previously asked Grisha, that he was the one who started this story, was he not?
This convinces Grisha to take up his scalpel and stab it through his hand. He then murders the Reiss family, with only Rod Reiss escaping.
Grisha leaves the chapel and his Titan, taking a syringe of Titan spinal fluid with him. He collapses, telling Eren that he killed the Reiss family and asks if he is happy now, if this is what he wanted. Grisha wants to know if this was what he truly had to do in order to save Eldia. But Eren does not reply. Grisha sobs, asking why Eren did not show him everything. He saw the Walls being destroyed, but not whether Carla is safe.
After a moment, he asks if Zeke is there, and tells him that everything will go Eren's way instead of Zeke's. Grisha saw Eren's memories of what is to come, and cannot believe it. He looks up, and truly sees Zeke this time. He stands up and apologizes for being a terrible father. Despite Zeke's apprehension, Grisha embraces him. He tells Zeke that he loves him and wishes he had spent more time playing with him. Overcome, Zeke calls him "Dad" and Grisha warns him that he has to stop Eren.
The connection between the two brothers breaks and they find themselves back in the desert realm of the paths. Zeke is shaken, but Eren is undaunted and tells him that they have not yet gotten to the part where he eats Grisha.
Zeke realizes now that Eren is the one who pushed Grisha to kill the royal family, and by extension, the rest of the world. But considering that the Attack Titan can transcend time, he is surprised that Eren also showed Grisha events that were unfavorable to him. Zeke concludes that Grisha was willing to steal the Founding Titan, even though he could not use it, because of a different memory Eren had shown him.
Eren thanks Zeke for making his plan possible by bringing him into Grisha's memories. When he kissed Historia Reiss's hand four years ago, he saw inside Grisha's memories, and within them, he saw his then future self and the sight of things to come.
Zeke panics and shouts for Ymir to steal the ability to reproduce from all Subjects of Ymir, causing the girl to turn away and walk towards the Coordinate. He tells Eren that he does not know what kind of future he saw in Grisha's memories, but he did not see everything, just as he did not know that he would be unable to use the power of the Founder here.
Eren's wrists are still shackled, but he frees himself by pulling so hard he rips off both thumbs. As he chases after Ymir, Zeke tells him that it is pointless, and that nothing in this world can stop her.