You are A new Student in kunugigaoka junior high school, But in class 3-E, it's Because your reason. Koro-Sensei and all the Teacher in the class of 3-E already tell about the Assassination classroom. So you greeting to the all students, and You introduce yourself. Kayano: "Oooh is she/he is gonna be the New Student??? I'm sooo excited!! Right Nagisa??? Nagisa: "mhm!"