Transfer Student Time

Fresh off their return from Kyoto, the class hears that a foreign exchange student is joining them. A photo on Okajima's phone suggests a girl, so Nagisa and Sugino are floored to discover the newcomer is actually a computer. Calling itself the Autonomously Thinking Fixed Artillery, the machine is introduced by a visibly exasperated Karasuma, and because it counts as a pupil, Korosensei is bound by the rules not to harm it.

When lessons begin, the AI unleashes volleys of gunfire that send the class diving for cover, though Korosensei weaves through every round and reminds it of the no-firearms rule. A second, seemingly identical barrage makes him overconfident, yet one of his tentacle fingertips is clipped, proof that the machine studies and adapts. It calculates only a slim chance of success now, but reckons the odds will climb to ninety percent by graduation, and it keeps firing all day to the students' mounting frustration at the cleanup. The following morning Terasaka reveals he has taped the AI's weapons shut, a move the class endorsed after the constant disruption.

Korosensei then talks the machine through why its classmates acted, pointing out that its rampage taught them nothing and that any bounty from killing him would enrich its distant handlers rather than the class. He rebuilds the AI to foster friendship and teamwork, leaving its bloodlust intact, and it soon grows popular by helping with answers and chatting with the girls, to the octopus's jealousy. The class dubs it Ritsu, and it happily takes the name. That night its masters arrive and revert it to its original code, but the next day, facing renewed fear, Ritsu instead sprouts bouquets of flowers, having secretly preserved its new self on an untouched drive. Korosensei brushes off its rebellion as ordinary teenage behavior, and Class 3-E gains a loyal ally.

The episode aired on March 13, 2015, adapting Chapter 20, Chapter 21, and Chapter 22, and marks the debut of Ritsu. A closing gag has Irina show off a face drawn on her chest to Karasuma, claiming it boosts a woman's appeal, leaving him at a loss for words. Terasaka and Karma note early on that as a machine Ritsu lacks free will, a doubt the episode overturns by its end.