KHR and Assassination Classroom crossover Tsuna was an assassin. His intuition and shot were unrivaled. He knew many people in the Mafia including the infamous assassin Serpentine. Nagisa was an assassin. He had a natural talent to kill. It was just simply that. Not to mention the fact that he was good friends with one of the most dangerous assassins ever, 27. The two teens struggle to hide their identity as suspicion closes in on them. "What do you mean that I'm an assassin, Koro-sensei?" "That's quite a wild conjecture, Reborn." I DO NOT OWN KHR AND ASSASSINATION CLASSROOM.