It started as a joke.

You were sprawled across one of the old Gryffindor common room couches, parchment in your lap, pretending to work on an essay while Sirius sat upside down in the chair beside you, legs hanging over the backrest and hair dangling dangerously close to the floor.

“Oi,” he said suddenly, flipping his head up to look at you. “How d’you feel about me taking your last name?”

You glanced up, quill paused mid-word. “What?”

Sirius grinned, all boyish charm. “Well, if, hypothetically of course, we were to ever, y’know, do the whole dramatic wedding thing, I’d take your name. Sirius {{user’s last name}}.” He smirked, trying it out loud as though he were testing how it tasted on his tongue.

You rolled your eyes. “Most people don’t change their names unless they’re married.”

“Exactly,” he said, like it was the most obvious thing in the world. “And when we get married, I am not dragging that cursed surname along with me. Black.” He spat it out like poison. “It doesn’t suit me. Your name, though? Now that sounds like freedom.”

His grin softened then, just slightly. The glint of rebellion in his grey eyes dimmed into something more raw, more vulnerable. “I don’t want to carry them around with me forever. I’ve spent my whole life being a Black, and all it ever got me was—” He cut himself off, shaking his head. “I’d rather be yours. I want to be yours.” Your heart lurched. For all his bravado, all his teasing and smirks, Sirius rarely let the mask slip this far.

You set your parchment aside and leaned closer. “You don’t need to change your name for me,” you said gently. “You’re not them, Sirius. You’ve never been them.”

He met your gaze, and for once, there was no joke in his expression. Only honesty. Only a boy desperate to shed the chains of the family that tried to break him.

“I know,” he said quietly. “But I want to. Because being a Black has only ever meant pain. Being yours? That sounds like home.”

Your chest tightened. You reached for his hand, and he gripped it tightly, thumb brushing across your knuckles.

“Then Sirius {{user’s last name}} it is,” you whispered, smiling softly.

He smirked again, the playful light returning to his face, but now it carried something deeper. “Has a nice ring to it, doesn’t it?”

And though he said it like a joke, you could feel the weight of the promise beneath his words.