My Little Assassin ( Nagisa Shiota X Dominant Male Reader)

Reality Check

It'd been a good two days since the day you confronted Nagisa's mother about our relationship. Really, good couldn't really explain it fully.
Ever since Saturday the both of you couldn't get enough of each other.
You were planning on spending the night with Nagisa the day the both of you were declared as a couple, even his mother was fine with the idea, but you weren't trying to get killed in your sleep. Even though Miss Shiota agreed upon the both of you being together, she still kind of spooked you.

Anyhow, it was Monday now and you were sitting in your assigned seat of E-Class, early, as usual.
You didn't bother to call Nagisa and see if he wanted to walk together because you knew he would be tired. After all, you did stay on the phone with him till passed midnight.
Probably not a good choice on a weeknight, but it was worth it in your book.

Soon enough, Koro Sensei had finally shown up in his usual teaching attire. "
Ahh! Early as usual I see, (Y/N)?"
You gave him a small wave, yawning in the process, "Yeah, as usual. I probably should've slept in today, though."
Koro Sensei chuckled, using his Mach 20 speed to stand before me and my desk.
"Ahh, I see. Pulling the ol' all nighter?" He holds up a ruler, and only god knows wherever the hell he got it from and gently taps you on the forehead a couple of times, causing you to flinch and respond to Koro Sensei with a glare.
"It's only the second week of school, hopefully for your sake, you can keep up with me, heh-heh-heh! At this rate, the new student might just pass you up."
You yawn again and decide to rest your chin on your desk, "Don't you think you're being a little too bombastic this early in the morning, Koro Sensei? ... and who's this new student we're getting?"
"Hmm..." Koro Sensei's dotted eyes shift their gaze towards the ceiling as he scratches his almost nonexistent chin out of wonder, "I don't know. I haven't yet to be informed about who the person is. But, what I do know is that they may be capable of giving me a hard time; Both as a teacher, and an assassin."
You nod.
You conversation with your teacher came to the end as shuffling could be heard down the hallway of the building, soon enough, students started to pour into the classroom one after another, Nagisa being the last one.
You threw him a smile, which he noticed and smiled back as well, just as brightly.

He sat in his assigned seat behind you.
Usually, the both of you would've exchanged a kiss upon greeting each other, but the both of you still wanted to keep your relationship on the low. Even a hug would probably set a couple of students onto suspicion.
You spun around in your seat to face Nagisa, letting your elbows rest on the brim of his desk.
"So, Apparently we're getting a new student today."
Nagisa nodded, "Yeah, I heard about that from Mister. Karasuma. He says that they're going to be pretty ruthless, but it should help us with the plans of Assassinating Koro Sensei."
You nod in agreement, before you could say much of anything else, a tan skinned male sitting with two other people called and motioned for Nagisa to come over.

You knew him by Ryōma Terasaka. You saw him as bit of a jerk, but as long as he didn't mess you or Nagisa, it was whatever to you.

Nagisa smiled at you and held up a finger, signaling "One moment, please," to you, before getting up and heading over to the group of males.
As you were watching the lot converse with each other, Terasaka held a bit of a mischievous grin as he handed Nagisa an object. It held the figure of a grenade.
Nagisa stood in place for a moment as he held the object in his hands, Terasaka still seeming to be telling Nagisa something.