Whoa whoa whoa. Koro-sensei was Shinigami? What. Talk about out-of-nowhere plot twists. And I thought Kayana's tentacles were a sudden surprise. I've got to say, I'm disappointed, Koro-sensei's backstory seemed pretty cliched so far. At least the whole blowing up the world and assassination thing are being explained. I'm not sure how black eyes suddenly transformed into Mr. Nyuruhuhuhu personality-wise, though, the difference is so drastic.
If you see that my post is exactly 1 month old (or more) from when it was posted... Don't waste your time, especially when you want to reply with something petty & insignificant. Assume that I've moved on (because I have).
That tongue! Nakamura and Karma were ready to capture that moment. Bitch-sensei seemed proud of Nagisa lol. In the end, even if Kayano was acting, she still developed a close relationship with the whole class but her tentacles were getting in the way. She was already past her breaking point and she needed help in the end.
It's nice to finally know something of Koro-sensei's past. I was confused at first when he announced that he was the Reaper but they addressed it immediately in this episode. Every assassin in this show isn't just random goons hired by the government to kill Koro-sensei but they're connected to each other one way or another. Koro-sensei was having a really bad day at that time, huh? His pupil betrayed him and he became a lab rat.