Episode Title:
Happy Birthday Time.
Episode Description:
With three hours remaining until the orbital laser cannon is charged, Nagisa and the others begin infiltrating the mountain. Using their home turf to their advantage, the students knock out all the police troops guarding the area and reach Koro-sensei, who praises their efforts for coming so far despite the odds. He calmly shares words of wisdom to his students, preparing them for the road ahead. Just as Nakamura bring out a cake and all the students celebrate Koro-sensei's birthday, Yanagisawa appears on the scene with The Reaper, who has been powered up with tentacles. Koro-sensei looks back to when The Reaper used to be his apprentice, but he never gave The Reaper his approval as an assassin. While The Reaper battles Koro-sensei, Yanagisawa injects himself with the tentacle formula and attacks Koro-sensei as well.
