After Asta receives a grimoire and joins the Black Bulls to become the new Wizard King, he explores a dungeon and meets Mars, a magic knight from the Diamond Kingdom.

Later on, the Black Bulls travel to the Underwater Temple and meet a series of challenges to find a magic stone (which the Eyes is also searching for).

The season initially ran from October 3, 2017 to September 25, 2018 on TV Tokyo in Japan;[2][3] Avex Pictures released it on DVD and Blu-ray in five compilations (each containing nine to 11 episodes) between February 23, 2018 and January 25, 2019.

[6][7] Funimation's adaptation aired from December 2, 2017 through January 6, 2019 on Adult Swim's Toonami programming block,[8] and they released the first DVD and Blu-ray compilations on August 7, 2018.

The first opening and closing themes (used for the first 13 episodes) are "Distant Future" (ハルカミライ, Haruka Mirai) by Kankaku Piero and "Blue Flame" (蒼い炎, Aoi Honō) by Itowokashi.