The Red Devil

After a quick recap of how the Demon King came to lead Class E, Koro-sensei stresses that the group needs stronger heroes if they ever hope to defeat him. Karasuma arrives to name three renowned prospects: the Red Devil, Karma, holed up in a northern cave with rare and formidable powers; the Evolved Mage, Ritsu, whose magic grows sharper by the day; and the Silver Berserker, Itona. The class sets out first for Karma.

At the cave, Koro-sensei hands each student a strategy guide cataloging the dungeon, its monsters, a sealed-off section of racier entries, and Karma himself. The book notes Karma carries a bug that tanks his luck stat whenever he grows overconfident. Inside, traps abound, but the teacher's speed lets him shepherd the class safely through, and he even repairs the hazards as he goes. The group is then cornered by a swarm of Mushroom Kunudons, harmless to the Demon King, until one of them severs Koro-sensei's hand and reveals itself as Karma in disguise.

The strike stuns everyone, since no one had managed to wound the teacher before. Karma taunts him, only for a washbin to drop on him and spring a trapdoor beneath his feet. An enraged Koro-sensei pounds the wall while Karma climbs back up and greets Nagisa, an old friend. Nagisa's pitch to join the party and help take the teacher down is refused, and Karma instead triggers a net trap meant for Koro-sensei, trying to stab him, only to find a Kunudon in his place. The teacher reappears, freshly bathed and drying his hair. Furious, Karma lunges again, and Koro-sensei responds by stripping the Red Devil's clothes and hauling him off to a hot spring, where he works to sell Karma on joining as their leader. Back in the cave, Karma allows that he 'might' sign on, and over his objections the class ushers him into their ranks.

Karasuma introduces the three sought-after heroes, and the class begins with Karma. Koro-sensei distributes strategy guides that expose Karma's luck-related bug. Karma, hidden among the Kunudons, becomes the first to injure Koro-sensei by cutting off his hand. A series of traps and counter-traps plays out between Karma and the teacher. Koro-sensei drags Karma to a hot spring to persuade him, and Karma is folded into Class E despite his protests.

This is the second episode of the Koro-Sensei Quest! anime, the RPG-world comedy spinoff, and it draws on the second chapter's material. It first aired in Japan on December 30, 2016, with an English airing on January 18, 2017. The opening is Re:QUEST! and the ending is a remix of Seishun Satsubatsuron. It follows The E Class and the Demon King and leads into The Seductive Witch.