The Apostles of Sephirah summon and open the gate to the Shadow Palace in order to complete the Reincarnation Magic. The elves Reve, Drowa, and Eclat stay behind to deal with the humans while the others head inside. Yami Sukehiro instructs the Black Bulls to deal with the threat while he and Jack the Ripper head into the Palace.
After the three elves are defeated, more elves arrive in Clover Castle, and the Shadow Palace's gate begins shrinking. While the other Magic Knights hold off the elves, Fuegoleon Vermillion, Mereoleona Vermillion, Mimosa Vermillion, Nozel Silva, Noelle Silva, and Asta fly through the gate before it closes.
Battle of the Shadow Palace
Asta and the others begin to notice the fluctuating magic around them around them as they move into the tunnel. Asta and Mimosa land in one of the lower areas of the Shadow Palace with Mimosa healing Asta to get him back to full strength and making a guide map of the whole Palace and how there are elves in most of the rooms. Asta and Mimosa encounter Lira, the elf that has possessed Rill Boismortier, and try to talk with him who refuses to listen to anything they say. Lira remarks how Rill's Painting Magic is far more effective than his Scribble Magic allowing him to create elaborate, deadly paintings to attack the duo. Meanwhile, Noelle encounters a revived Fana, Mereoleona fights a revived Vetto, and Fuegoleon fights a possessed Kaiser. Later on in Noelle's fight, Jack arrives to assist Noelle.
During these fights, Yuno arrives at the Capital with several Magic Knights in order to assist the Black Bulls in their fight against the elves. Charmy approaches Yuno and gives him some food in order to help him recover his mana. She then goes with him to the Shadow Palace with Nero failing to stop them from entering the palace with Yuno's necklace. Charmy ends up being separated from Yuno and arrives at Asta and Mimosa's fight. Lira starts to panic with him noting his destructive paintings and how he never wanted to make these destructive creations. Charmy approaches Lira with food attempting to calm him down but he knocks the food out of her hand enraging Charmy who attacks him with Sleeping Sheep Strike. Lira knocks Charmy aside but then notices Charmy changing into a taller slender version of herself recognizing her as a dwarf-human hybrid. Asta is informed by Mimosa of the Dwarves abilities and disappearance with Charmy being freaked out by the revelation of her lineage along with her Sheep actually turning out to be a Wolf which is a manifestation of her second magic attribute, Food Magic. This magic allows her to consume Lira's magic giving her enhanced strength putting Lira at a disadvantage. Charmy takes over which gives Asta and Mimosa the chance to move onward. The two find an unconscious David Swallow possessed by the elf Baval and learn Yuno arrived in the second top most room with there being two elves in the room with him. Rhya, Patolli, and Ronne confront Yuno in the room and demand he hand over his amulet to complete the reincarnation spell. Yuno uses his Mana Zone against the trio to try and defeat them but is unable to injure them and his amulet is taken by Ronne using his Switching Magic. However, Rhya notices something off about Ronne and questions who is actually talking at the moment. Ronne then has a devilish smile on his face and blasts a giant hole in Rhya's stomach.
As Rhya collapses from his wound, he thinks back on how he kept up the lie that Lemiel Silvamillion Clover betrayed and killed the Elf Tribe in order so the others would continue hating the humans. Rhya remarked on how he wanted to see the others especially Licht again noting that this lie made his moniker of "Disloyal" quite fitting. Patolli runs over to heal him and starts to ask Ronne what is going on. Ronne moves over to the stone tablet and places the amulet on it which causes black substance to form from it with something leaving Ronne's body and entering the substance saying it is home. Yuno, Patolli, and Rhya all are freaked out by the being which is shown to be a devil. The devil remarks how he finally was able to regain a body and plans to complete the rest of his plan revealing to Patolli that it was not Licht who activated the Reincarnation spell but he himself. He also revealed that it was his deception that led to the Royal family from 500 years ago except Prince Lemiel to destroy the elves. As Patolli launches his Light Sword of Judgment at him, the devil tells the swords to return with Yuno barely being able to save him from the incoming attacks to save William Vangeance's body from harm. Yuno and the arriving Asta try to attack the devil but he effortless pins the two to the ground with a vacuum wall while impaling Patolli on iron spears using his Kotodama Magic. The devil taunts Patolli with the fact that Licht never wanted revenge on humanity and that his actions helped the devil's plans go through without fail. Despite his desperate pleas for all of this to be a lie, Patolli screams out in despair with the devil gloating at how he has made the elves and humans into his playthings and Rhya apologizing to Patolli for not stopping him from doing wrong. Though Asta and Yuno get up and attack the devil, they barely do any damage to him and he takes Patolli's grimoire, which became a five-leafed one due to Patolli's despair for his plans. Using Patolli's new found grief and despair, the devil causes Patolli to become a Dark Efl and has him attack Asta and Yuno while he leaves for the outside world. The duo are effortlessly pushed back by Patolli's increased strength but they are saved by Nozel who uses his Mercury Magic's elemental advantage over Patolli's Light Magic along with Patolli's lack of thinking as a dark elf to easily defeat and restrain him. Rhya starts to pass away remarking how he failed all of his friends but is saved by Mimosa who is able to help close up his giant wound. Though Nozel wants to finish Patolli off for his previous actions, Yuno and Asta convince him to let him live out of concern for WIlliam and to Patolli out, respectively. Using Asta's Demon-Destroyer Sword he tries to dispel the reincarnation but is instead drawn into Patolli's mind where he sees all that Patolli is thinking of and done including his recent killing of Julius Novachrono. Patolli, still represented as his younger self in his mind, reflects on all that he has done but still tries to blame humanity for his people's destruction. Asta soon confronts him about his attempted attack on the capital which he used to kill Julius along with his reincarnation causing damage throughout the country. Asta tells Patolli that despite his anger towards him, he wants him to stop running away from his issues and try to stop the devil from causing more pain. This along with Asta's statement that even if you are not forgiven for your mistakes that you can still move forward helps Patolli break out of his dark elf form. Patolli promises to help Asta and the others defeat the devil.
The devil soon makes it to the top floor where Licht, still in a semi-comatose state, confronts him with Yami along with Charla (who is possessing Charlotte Roselei) joining in to help him. Charla points out that Baval went into the Shadow Palace which led her to follow him. (This was due to Baval being possessed by the devil at this time. When they arrived in the Shadow Palace, he possessed Ronne to get closer to the tablet and left Baval lying unconscious). Though Yami was able to cut his left hand and wing off, the devil proceeds to reattach them with his magic commending the teamwork of the elves and human but also saying how he cannot be beaten. Yami proceeds to remark how the devil is a lot more powerful in his magic ability but also points out his weaknesses including the fact that he has to doing Yami's Dark magic. Growing tired of the fruit game as well as to get rid of Yami, the devil uses Patolli's grimoire to use his magic to open a portal to the underworld. This magic is able to absorb all magic which forces Yami to knock Charla out of the way. Yami's right hand was drained of mana which prevented him from using his sword. The ooze the proceeded to drain down to the area where Asta's group is and Patolli upon having some of it fall on his shoulder notices how it is damaging to the body. Asta knocks Mimosa and Rhya out of the way but is saved due to his body not having any magic. Nozel decides to split up from Asta taking Mimosa, Rhya, and an unconscious Ronne with him while Asta, Yuno, and Patolli head up to confront the devil.
Meanwhile, Nero flies over to Finral, pecks him to get him to wake up and speaks to him for the first time to tell him to go get the magic stones and go to the Demon's Skull near Hage. After taking the stones out of the tablet, Nero has Finral place the stones into the First Magic Emperor's statue on top of the skull. Upon completely filling in the spots on the statue, it is revealed that the statue was actually the First Magic Emperor, Prince Lemiel, who was sealed after his battle with the giant demon by Nero 500 years ago. Nero turns out to be a girl named Secre Swallowtail who served Lemiel and goes back into her original form. Nero and Lemiel head towards to the Shadow Palace with Lemiel's Light Magic and Secre using her Sealing Magic to open the portal up. The duo thank Finral for his assistance and promise to bring Asta and the others back.
Asta, Yuno, and Patolli arrive to confront the devil who is surprised.
After escaping the Shadow Palace, Patolli allows Asta to dispel the Reincarnation on himself thus allowing William to reawaken. William and Licht perform a combo spell which connects all the elves' souls to a tree which allows Asta to dispel it. All the elves leave their bodies except Rhya, Vetto, and Fana due to them being affected by the spell twice. Licht encourages the trio live their lives out for the rest of the people and thanks Yuno for allowing him to fight alongside his son in a way. Before he leaves, Asta tries to give Licht his Grimoire back but he tells Asta that it belongs to him now and tells him to take it with him wherever he goes. But before the elves fully depart, Rades uses his Soul Abductor spell to place Patolli in Licht's artificial body so he cannot have a happy ending after all the suffering he has caused others.