Takes place in the dorms and the students of 1-A know that Izuku is a vampire. I don't know if I want to reveal it by then, but let's assume for now.
"Hey, Midoriya. I've been wondering for a while, but... why are you Japanese?"
Izuku looked up from his very-comfortable position of snuggling with (a rather tense) Toshinori. Tilting his head to face the speaker, he made a questioning sound at the strange inquiry.
Kirishima took that as a signal to continue hdis line of thought. "I mean, you're a vampire, right? Isn't that a Western thing?"
Stretching, Izuku got off Toshinori reluctantly. It had been a rather trying day of human cheerfulness and coldness.
"Not really. Just because the word 'vampire' first originated in Europe doesn't mean that the species hasn't existed before then. In fact, vampires in East Asia tend to be misidentified as kyonshi."
"Kyonshi?"
The other children who were previously occupied by other activities began to turn to face the red-eyed creature. Even the youngling, who tended to be too lazy to actually learn at times, began to take some interest.
"Kyonshi are reanimated corpses. They feed off the life energy of the living, usually chi or something. Though, I'm surprised, Kirishima-kun, I wasn't aware that you knew about the origin of vampires."
"Oy, oy, I know I'm not that smart, but I do know how to use the internet."
"The what?"
"...Nevermind."
Izuku raised an eyebrow as he watched half of the inhabitants of the room hold back their laughter. So what if he didn't know what kids these days like? It's not like he'd ever need it...
"Y'know... that's kind of creepy," Toshinori muttered behind him.
"How so?"
"Well, isn't it basically forcing a dead person to come back from his or her resting place?"
"Hmmm... I suppose. Though, they generally don't remember much, and depending on the creator, don't tend to stick around for a long time. They are forced obey their creator, though there are exceptions. It can get a bit complicated."
"I-I see..."
"... Kyonshi aren't as terrifying as they sound, Toshinori-san. In fact, I know a couple of them. Their personality varies based on the creator and themselves back when they were alive."
"Midoriya-kun," Iida began to speak, pausing in his conversation with Uraraka, "You know some kyonshi? What are they like? Are they as old as you are? If so, how are their creators still alive? How are - "
Izuku sighed. As cute as it was that Iida was interested, there was a limit to how much verbal spewing that he could take.
"Yes, they're all a bit different, no, and that's a different matter altogether. The eldest one is about two hundred years old, as a kyonshi. He's a bit... air-headed, you could say, but he's a good friend, I suppose. The other one's are about ten to hundred years old."
As the other students quietly digested the information presented, Izuku turned away from the group, hoping to find something warm to snuggle with. What a curious group of children.
Now that he thought of it... Maybe he should take visit to that air-headed kyonshi. Who knew what that moron might've done by now?
Happy New Years!