As life slowly returns to normal in the royal capital, the Wizard King reaches an uncomfortable conclusion about the invasion and how it came about.

Asta attempts to tap into his mysterious dark powers so he can make it to Mereoleona’s hot spring training camp. Noelle learns about her late mother.

It’s the final match in the Royal Knights Selection Test. Rill seeks inspiration for his masterpiece; Yuno and Bell are ready to try something new.

Noelle and the other Black Bulls head to Racquey to do some training, when Noelle hears a mysterious voice. Shortly after, the Black Bulls are reunited with Kahono and Kiato. The siblings ask them for help and they head down to the Underwater Temple. There, Gifso explains that a creature called the guardian has gone berserk, so in order to quell its rage, Kahono and Kiato need to present it with their song and dance. Gifso asks the Black Bulls to act as their bodyguards and Yami appoints Noelle and Finral for the job.

Asta and Noelle are captured along with Nero and they head toward the strong magic region near the border when Captain Yami and Magna arrive. Captain Fuegoleon and Captain Nozel also show up, causing the Devil Believers to panic. The captains try to talk to the Devil Believers, but their distrust for them is just too strong. The Devil Believers try to bring their powers together in order to face the Magic Knight captains.

The Magic Knight Squad Captains gather for a meeting and for an award ceremony with the king later. At the meeting, they decide that Asta, Nero, Noelle, Luck, Finral, Mimosa, Leopold, Charlotte and Rill will be going to the Heart Kingdom to train with the Spirit Guardians. At the award ceremony, Yuno advances very quickly in rank.

Months after arriving at the Heart Kingdom, Asta still doesn’t have any magic, but he’s become more powerful at an alarming speed due to his training with the Spirit Guardians. Anti-magic is one of the magic attributes that falls into the “Arcane Stage” and is needed to defeat the devil. And because of that, Gaja asks Asta how exactly he obtained the five-leaf grimoire.

The War against the Spade Kingdom begins in earnest as the Heart Kingdom and Black Bulls come under attack by Dante and Vanica of the Dark Triad.

Due to Nacht's spell, the Devil who has been granting Asta power since the beginning has appeared physically. To master his Devil powers, Asta must battle and defeat his Devil, and force him to submit. But Asta has other plans... Meanwhile, Yuno, Noelle, and the others grow stronger in order to take their revenge against the Dark Triad.