It started in the Heights Alliance common room, long after classes had ended and the sun had dipped behind the buildings outside. Books were scattered across the coffee table, snacks half-eaten, and a dull, exhausted kind of peace had settled over the dorm like a blanket. Denki was on the couch, messing with a glitching tablet. Kirishima lounged across the armrest with a protein bar in one hand and highlighter marks on his face. Bakugo sat on the floor beside the couch, legs crossed, flipping through his notebook with furrowed brows and a scowl of concentration.

You were sitting beside him, leaning back against the couch with your own textbook open lazily in your lap, one leg stretched out so your socked foot nudged his shin.

“Katsuki,” you said without thinking, nudging his arm with your pencil. “You spelled ‘combustion’ wrong again. You forgot the ‘ion.’”

It was casual. Thoughtless. Natural, even.

And then—silence.

A sharp, frozen kind of silence fell over the room like glass shattering in slow motion.

Kirishima’s head whipped around so fast his snack wrapper flew off his lap. Denki sat up straight, blinking rapidly, tablet forgotten on the floor.

Sero, who hadn’t even been part of the conversation, slowly pulled out his earbuds with the same look people got before a hurricane hit.

Kirishima’s voice cracked the silence first. “Wait. Did you just—did he just say your first name?”

Denki pointed. “He did! You did! He said Katsuki—like it was nothing! Just slipped it in!”

You blinked, confused. “Uh. Yeah?”

Denki gaped. “And you’re not dead?”

Bakugo didn’t look up. He just kept flipping through his notes like the room wasn’t holding its collective breath.

Kirishima glanced between you and him, wide-eyed. “Dude. You let him call you that?”

“Why wouldn’t I?” Bakugo muttered, finally scribbling something into the margin of his notebook. “He always does.”

That only made the other two panic harder.

“Always?!” Denki all but shrieked. “You blew up my shoes when I tried that in first year!”

“Yeah! You said if I called you that again, you’d blast my mouth shut!” Kirishima added, eyebrows raised so high they nearly vanished into his hair.

Bakugo sighed through his nose, barely glancing up. “That’s because you two are annoying.”

The sharpness in his voice wasn’t even angry. Just factual. Bored, even. Like the subject didn’t warrant his attention.

Denki, never good at knowing when to stop, tried again. “But like, now we’re closer, right? So can I—?”

“Try it and you’ll be scraping your teeth off the wall,” Bakugo snapped without even looking.

Denki flinched back behind Kirishima. “Okay! Copy that. Message received. First-name privileges denied.”

Kirishima raised both hands. “Hey, no argument here. I just wanted to witness history. That was wild.”

You tilted your head and looked over at Bakugo, amused. “Seriously? You don’t care that I call you that?”

He glanced sideways, face unreadable, then rolled his eyes and went back to his notebook.

“…You don’t say it like it’s a joke,” he said quietly. “That’s why I don’t care.”

The words were simple. Dismissive, if you didn’t know him. But you did. And in Bakugo’s language, that was practically a poem.

Denki groaned dramatically on the couch. “So that’s it? He just gets a special pass? No lecture, no boom?”

Bakugo didn’t answer. He just bumped your knee with his and kept working.

Later, when the others left and the room fell into that peaceful nighttime lull, Bakugo leaned back beside you, shoulder brushing yours.

“…Don’t stop saying it,” he muttered.

You looked at him, startled.

He didn’t meet your eyes.

“Not used to people saying my name like that.”

You nodded once, soft. “Okay.”

And you meant it.