Behavior Analysis (Assassination Classroom x ???)

Exchange

"You will be meeting two professionals today, one will join the class and the other will teach a class" The class started to talk and I heard a lot of questions. Is it a boy or a girl?, are they hot?, are they nice?, and many more. I stared out the window and thought i saw a speck of movement but brushed it off as the leaves. "Hey! Long time no see! How's your life been?" As we faced the front we saw a male in a collared shirt that was covered by a white sweater. He also had on black glasses. Most of the people were staring at him as i looked to see a startled Koro-sensei.

"Y/n! Wh-when did you get here?!" The male named Y/n stared outside in thought. "I walked inside the classroom at 7:15 so ... An hour ago?" We were all stunned, even Karma who was ready for anything! "That's a load of bullshit! We would have seen you at some point!" Most people looked around the room agreeing with Terasaka and when they looked back at the front the man was gone. "What did you say about noticing me? all i did was walk up here and nobody even noticed i moved." With a sweat drop Koro-sensei walked behind Y/n only to have his arm cut off. " Please don't touch me, i would hate to waste all of the hours you spent training them only to kill you myself."

I heard a scoff from the back and noticed Karma was staring strait at him. "Trust us, you can't kill him yourself 'sir'.'" He said making quotation marks with his fingers. The man chuckled and looked back to see a cowering Koro-sensei. "N-now now Y-Y/n remember that you said you were only here for training purposes." Y/n nodded and disappeared again only to be found in front of Karma's desk. Much to everybody's surprise. He raised his hand as if to smack Karma but then stopped a little bit short and ruffled his hair. "Your very talented, please don't be rash. I was only stating the facts." We all looked over to see Koro-sensei nodding. "He's the only reason i'm allowed to run this class! One foot out of line and he'll kill me!" I started to jot things down in my notebook and almost had a heart attack when Y/n stood in front of my desk

"Also i will be joining your class as a new student seeing as my stature is only a little different from everyone else's. Based on his body composition he looked like he was 19 at the most but his knowledge and maturity was that of a man in his late 40's. " umm sir i know this isn't exactly the most appropriate question but how old are you in all actuality? " he wrote something on my notebook page and walked up to the front. "I'm 16 until December 7th." Nakamura who was drinking a fruit juice at the time spit it all over the desk. "Your what?! I thought you were at least in your early 20's!" He shook his head and turned to the board beginning to write something as we watched Koro-sensei take off from the window.

We heard a knock on the door before it was pulled open. With a shocked look Mr.Karasuma's gaze settled on Y/n who had yet to turn around. "Y-Y/n to what do we owe the pleasure of such a high ranking assassin to gather here?" He said clearing his throat before gulping. "He nodded at Mr.Karasuma before taking off his glasses. He appeared suddenly over to him and loosened his tie which shocked all of us. " I've told you before to loosen up, having that tie always around your neck isn't going to help your health." I let out a sigh of reassurance as i heard he was NOT doing anything umm ... 'weird' to him. Mr. Karasuma looked us alk down before sighing. "Anyways, Y/n here is the #1 ranked assassin in the world. I may not have any idea what he is doing here but keep in mind that he is very, very dangerous."

Karma got that kind of crazed look on his face as he heard this and started to flip his pencil in the air. Looking down to write another note i noticed the neat writing on it. 'I like your hair!' I blushed slightly and laughed a little earning a confused stare from Kanayo. I shook my head and looked at the writing. 'This will be very interesting...'