After five years of civil war, the situation in Fodlan was finally starting to improve. Under the direction of the acting archbishop, Byleth Eisner, the three rulers of Fodlan had agreed to a truce in order to attack their true enemy - Those That Slither in the Dark. Edelgard agreed to stop attacking the Alliance and Faerghus, and the Adrestian Empire would gain full independence from the church. The Alliance would maintain its autonomy, and Claude would be free to build relationships with any countries he wished without interference from the church. Dimitri would no longer blame Edelgard for the Tragedy of Duscur and would atone for his earlier behavior by spending the rest of his days rebuilding his war-torn country. As acting Archbishop, Byleth would shift the Church of Seiros from a political organization to a humanitarian one. Its primary task would be helping people get back on their feet after years of war. Byleth and Dimitri, who had fallen in love, had married the night before in a private ceremony. They had wished to be married before fighting. The former classmates were thrilled at the union but agreed to keep it a secret until the war was officially over.
As Byleth prepared to address the war council, the mood was optimistic. The destruction of Fort Merceus was devastating, but it had given Hubert solid leads on the location of the Agarthan base, and Linhardt and Yuri had found some promising information in the Shadow library. To see her former students gathered now under one cause made Byleth feel elated. She asked Hubert to share his information with the council. As Hubert rose out of his seat, a figure appeared in a purple cloud of smoke. "Thales," Hubert snarled.
Thales stood in front of the council, grinning and holding a black glass sphere. "Now, Hubert, that is no way to talk to someone that did so much for you and your beloved Flame Emperor."
Felix rushed him and said, "What kind of fool appears in front of some of the most heavily armed people in all of Fodlan?" Thales cast a spell and threw him into the wall.
Thales held up the sphere and said, "Now where was I? Oh yes, see, you were all behaving so well. Edelgard, we gave you everything you needed to reshape Fodlan into whatever you wanted. Dimitri, what happened to vengeance for Duscur? It used to be the only thing you cared about. And Claude, you were so occupied playing games and keeping your petty little lords in line. And suddenly, you insects think you can conquer the true Children of Man with just your power of friendship? What a disappointment you all are. But I am a generous man, so I will bring you a gift. Now you all can spend all your time together!"
He smashed the sphere on the ground and yelled, "For the Agarthans!" Black tendrils extended from the globe. They climbed the walls and wrapped around the former students as they tried to escape. Hubert tried to warp Edelgard out, but his magic failed. Claude tried to force open the exits, but the doors were sealed. Seeing there was no way out, Dimitri wrapped his arms around Byleth and said, "Just hold on to me, Beloved. Whatever happens, don't let go."
As the tendrils wrapped around them, Dimitri began to disintegrate. Byleth cried out for him and tried to grab him, but she found herself being torn away. Blackness was all around her. She began to see scenes of her life play out before her eyes, but these scenes were soon replaced with new memories and a new life. Her body began to disintegrate, and she let out one final scream.