The first-class contributor who led the war against Ares to victory, the genius war hero of Athens, Nina. Nina vows to take revenge on Matthias, who killed her sister, Arde, who raised her, and declares that she will marry him. She intended to take her life into her hands and make her writhe in agony. She was planning the most terrible revenge. However, there was also someone she could not predict. "You and I are the same. Once you kill someone, it's the abyss, the abyss. The person you killed must have been precious to someone too." "I know that the dead do not come back. Still, I want to atone to the living... and be saved." Matthias, a war prisoner who has lived a life solely devoted to war like a tool. With the sole desire to belong to the Ymir family, Matthias, who wandered the battlefield, finds all of Nina Bertha's words unpleasant. However, at some point, he begins to feel an unknown emotion. "...You said it first. The dead do not come back." "You annoy me... I can't stand it." Can revenge be atonement? Can atonement be salvation?