After six months of training in the Heart Kingdom, Asta and his fellow Magic Knights have grown greatly in terms of power. The Spade Kingdom begins their invasion of the Clover and Heart Kingdoms, with the Dark Triad leading them. Zenon and his Dark Disciples attack the Golden Dawn to capture William Vangeance, Dante fights the Black Bulls to capture Yami, and Vanica and her Dark Disciples fight the Magic Knights in the Heart Kingdom.
Despite the Magic Knights' best efforts, the Dark Triad has captured Yami and Vangeance, the mages needed to form the Tree of Qliphoth to bring devils to the living world, and Lolopechka, the ruler of the Heart Kingdom. In the process, Zenon and his Dark Disciples kill half of the Golden Dawn, and Vanica detonates her Dark Disciples, ravaging the Heart Kingdom.
To the gain the power needed to help Yami defeat Dante, Asta asks the Anti-Magic Devil to lend him his true power. He agrees to a "devil's bargain", taking control of Asta's right arm as the price. The main trio (Asta, Yuno, and Noelle) are spread out throughout the continent and facing a different member of the Dark Triad shortly after Asta separates from Noelle following their completion of a mission against the Spade Kingdom.
Yuno learns about his heritage and he and the Golden Dawn fight Zenon and his Dark Disciples when they attack their headquarters to try and capture Vangeance.
Asta and some of the Black Bulls (Gauche, Vanessa, Grey, and Henry) fight Dante, who is trying to capture Yami, near the border of the Spade Kingdom. Yami and Finral later join them when he returns from the captains conference.
Noelle, Lolopechka, and Nero fight Vanica when she invades the Heart Kingdom to wipe out Lolopechka and her Spirit Guardians, with Luck, Leopold, Charmy, and Mimosa fighting Vanica's Dark Disciples.