Marcus Black walks through the plains towards Chaldea and comes across an area with really tall grass. Ushiwakamaru meets him. He calls her rude for not greeting her father, but she calls him out on abusing Mercury and destroying his legs. He dismissively says Mercury was weak, unlike her. She draws her sword and says her mother was right, he only cares about results, not them. He laughs and says keeping her away from him was probably her mother's last request, then asks if she knows how she died. She says her mother passed away of an illness, then asks how he knows she is dead. He says it wasn't an illness; he poisoned her. Enraged, she says she will kill him and attacks, but he catches her sword.
Jack the Ripper suddenly jumps out of the tall grass and stabs Marcus, forcing him to let go. He complements her for being a fighter at her age and for immediately targeting a weak spot, as if he hadn't turned at the last second, her knife would have pierced his kidney. Jack says she'll pierce his heart next time and disappears into the tall grass while Ushi prepares her sword. He says this two-pronged attack is a sound strategy, but it won't be enough. He pulls out a vial with a green liquid and drinks it. Ushi tries to attack him, but he finishes drinking and throws the vial at her, forcing her to briefly stop. He slashes the air with his hand, creating Razor Wind that leaves a cut on Ushi and chops down the grass in a ten meter radius. Ushi asks how he did that, and he says that drink had Wind Dust in it. Ushi realizes that though Jack is still hidden, with this wide open circle, she can't sneak up on him so easily. Marcus and Ushi have a Single-Stroke Battle, her sword versus his fist. Marcus gets a small cut on his arm, but Ushi's sword breaks. He throws another punch, but Ushi catches it and locks him in an armbar, trying to break his arm, but he lifts and kicks her, sending her flying as Jack watches in horror.
Marcus offers Ushi to be his apprentice, but she says she would rather die. He says she's a waste just like Mercury. Jack suddenly shrouds the field with fog and chants, "Hell is starting. We are flame, rain, power... Let there be a slaughter... Maria the Ripper!" She darts out faster than he can track and stabs him several times, making him staggernote . She tries to stab him in the heart, but he grabs her head and painfully squeezes it.
Ushi tells him to let her go, but he says Jack is a real fighter, so he'll make her his apprentice. Ushi dejectedly says she'll go with him if he lets Jack go. He tells her to prove herself by bringing him Mercury's head, but Jack suddenly stabs his arm and forces him to let go. He angrily kicks her in the leg, breaking it. Ushi runs to her and holds her as Jack clutches her leg and silently sheds tears from the pain. Marcus' wounds are not healing, but he is unaffected and he explains he took a potion that renders him numb and removes his fatigue. He says they lost and he still wants Ushi to bring him Mercury's head. Suddenly, Mercury arrives, flying through the air at high speed. He kicks Marcus, making him go flying and make a trench in the ground where he landed, and tells Marcus to stay away from his family.
Earlier, Mercury woke up and was shocked when he looked out the window and saw several teachers and students fighting off Grimm. Kato Danzo, in another bed with her prosthetic arms removed, and Nursery Rhyme in another bed say there is an invasion and everyone is fighting except the seriously injured. He finds the note Jack left him and sheds a tear when he reads it. He asks where Jack and his sister are. Kato says Ushi told her about their father and explains Ushi and Jack went to intercept him. Shocked, he says they can't fight him alone and he has to help, but finds his prosthetic legs are gone. Kato summons a new pair of prosthetic legs and says a few days ago, she took his measurements while he was asleep and forged these legs as a Noble Phantasm. She'll let him use them if he promises to come back alive. The legs have little metal wings coming from the ankles. He attaches them and says he feels really light. She says the legs are enhanced with wind runes from Medea and are many times stronger than his old ones. Nursery Rhyme shows her scroll which shows Jack's location. He opens the window and promises to bring them back. He channels wind from his legs and is amazed when he flies through the air with no wind resistance. He quickly finds the people he was looking for and kicks Marcus, telling him to stay away from his family.
Ushi and Jack are shocked and happy to see him, and Mercury is horrified when he sees Jack's leg. He tells them he got Jack's note, and to rest while he takes it from here, and he will cook Jack her favorite meal when it is over. Ushi says he can't fight Marcus alone, but he tells her to look after Jack and he is finishing this, one way or another. He reads Jack's note, which simply reads, "We love you." He smiles and puts it in his pocket.
Marcus emerges from the dirt and Mercury greets him, commenting the last time he saw him, he killed him and set his body on fire. Mercury then guesses something Marcus drank saved him. Marcus confirms it and removes his damaged vest to show burn scars on his body from that night. He says Mercury was always too lazy to confirm a kill, but he left him for dead and stole his next job. Mercury points out he destroyed his legs, so they are even, but he will never forgive him for hurting Jack and his sister. He is not afraid of him anymore. They fight, and Marcus is shocked when his blows fail to damage Mercury's legs. Mercury confirms Kato was right about the legs being stronger, but feels fatigue because he's still recovering from Round Two. They clash again, and Marcus demonstrates that no matter how strong his legs are, the joints are still vulnerable. Mercury's knees start clanking from Marcus' powerful blows. Mercury tries to think of a solution. The last time, he beat Marcus by ambushing him while he was coming home from a mission drunk. He gets an idea.
Mercury blitzes Marcus with incredible speed and hits him several times until Marcus manages to damage his knee with another hit. Mercury reveals he snatched all of Marcus' vials from his satchel. He confesses that those times when he raided his alcohol stash, he never drank it, he just smashed the bottles, then he throws down some vials and stomps on them. Marcus says he made a huge mistake and lunges at him, but Mercury throws a red vial at him. It shatters against his chest and sets him on fire. Mercury says he remembered what each of his brews do. As Marcus is distracted trying to pat the flames out, Mercury knocks him into the air with a few kicks, then flies up and gives him a huge German Suplex where Marcus lands directly on his head.
Marcus reveals his neck is broken and he's now paralyzed from the neck down. He tells Mercury that his father killed his grandfather and he killed his father. Now Mercury will continue the cycle and become just like him. Mercury says he'll do his best to make sure that doesn't happen and walks away. Marcus roars at him to come back and kill him, but in his excitement, he moves his head too far and dies. Mercury looks back and sighs when he realizes what happened. He comes back to Ushi and Jack, whose leg is in a makeshift splint, and says it's time to go home.
