The E Class and the Demon King

In this reimagined setting, Kunugigaoka becomes a magical academy that trains heroes, and the students of class 3-E are the ones saddled with bugs that leave them weaker than everyone else. The Demon King strides into their homeroom and calmly opens the lesson, inviting his class to strike at him as he greets them. Their assault leaves them spent while he remains untouched, and he chides them for how far they still have to climb, prompting complaints about their low levels and shoddy gear.

The episode illustrates their handicaps with running gags, such as Yoshida being able to wield only bathroom implements as weapons and Isogai managing to afford just the front half of a suit of armor. A flashback fills in the backstory: Karasuma, cast here as a commander, explains that these very glitches are the students' hidden advantage and the key to one day bringing the Demon King down. The villain himself admits his motive is simple, he wants an opponent who can meet him as an equal. The introduction closes with Fuwa poking through the fourth wall to ask about the story's limits, a nod to popularity votes deciding who drops out, and the class settling on a nickname for their teacher: Koro-sensei.

A separate beat shows Takebayashi joining 3-E after the principal, Gakuho Asano, humiliates him over a public announcement. Back in the present, Koro-sensei introduces the class to their first true foe, the slime. The creatures initially fawn over him, recognizing their Demon King, until they learn he intends to hand them over to the humans, at which point they scatter and the students give chase. The hunt goes poorly until Nagisa's randomized bug kicks in, letting a fire spell rout the slimes with ease. The catch is that Nagisa cannot revert afterward and has to turn to Koro-sensei for help.

The RPG-world premise is established, with 3-E recast as bugged hero trainees and their teacher as the Demon King. A flashback reveals Karasuma's role and the notion that the students' bugs are their path to victory. The teacher earns the name Koro-sensei. Takebayashi's entry into the class is shown. The group faces the slimes as their opening enemy, and Nagisa's bug activates, winning the fight but leaving him stuck in an altered state.

This is the first episode of the Koro-Sensei Quest! anime, an alternate-universe comedy that swaps the assassination premise for fantasy adventuring. It debuted in Japan on December 23, 2016, with an English airing on January 11, 2017, and adapts material tied to the first chapter. The opening is Re:QUEST! and the ending is a remix of Seishun Satsubatsuron. It leads directly into The Red Devil.