Third Period: Itona Horibe's Time

Itona rains blows on Korosensei from above while the teacher is snared in Shiro's bedsheet trap, a plan lifted from the students' own summer attempt. Korosensei counters by learning and adapting, storing just enough energy to burst the netting without a massive blast. Because Itona's attacks barely change from earlier clashes, the target defeats him with ease and again invites him into Class E, but the boy doubles over as his tentacles torment him.

Seeing that the endless losses are letting the tentacles eat into Itona's brain, and unwilling to bear the upkeep cost, Shiro abandons him without concern. The pain drives Itona into a rampage through town, though only cell phone shops are hit. Karma pegs Shiro as a man who spends subordinates like pawns and suggests leaving Itona be, yet Korosensei insists he will never abandon a student.

When Korosensei and the students corner Itona, smoke floods the area with a weakening spray, and Shiro's men seize the boy, revealing the desertion was staged. Itona recalls being taken in by Shiro on the streets after his own father cast him out, his hunger to win the only thing left to him. The full class then arrives to help, with Hayami stating flatly that their anger is aimed at Shiro for using them as tools. The rescue succeeds, Shiro's men fall, and the strategist retreats, warning that Itona has only about two days to live.

Fuwa traces Itona's father to a shuttered factory that once supplied smartphone parts worldwide, closed under mounting debt while his parents disappeared, which explains the boy's fury toward phone stores. Terasaka's group takes charge of his recovery, trying ramen from Muramatsu, a rough ride on Yoshida's motorcycle, and a book suggestion from Hazama. When the pain flares again, Terasaka confronts Itona, vowing to keep attacking Korosensei no matter how many failures pile up, and his words break through so Korosensei can safely remove the tentacles. The next day Itona joins Class E and Terasaka's group, pledging to keep up the assassination alongside new friends.

The third season-two entry adapts chapters 84 through 87. It premiered in Japan on January 21, 2016, with the broadcast dub on February 24, 2016, carrying the QUESTION opening and Kaketa Tsuki ending.