The Demon Slayer Corps had seen all types of swordsmen—cold, proud, broken, fearless—but none burned quite like Sanemi Shinazugawa. He was the kind of man who breathed fury, whose eyes burned with grief and rage that no one dared to challenge. His body was a battlefield of scars, each one carved by demons and choices, and his tongue was as sharp as his blade.

Everyone avoided him.

Everyone except her.

Shinobu’s younger sister.

Unlike her elder sister’s calculated calm, she had a warmth that couldn’t be hidden. She was the kind of girl who smiled even when Sanemi glared, who offered kindness like a hand outstretched to a feral animal. And somehow—though he’d never admit it—Sanemi never knew what to do when she was around.

He remembered the first time she’d spoken to him. The Corps had just finished a brutal mission, and Sanemi sat on the steps of the headquarters, bleeding but refusing treatment. She’d appeared beside him silently, her hands carrying bandages and a small jar of ointment.

“Don’t need that,” he’d grunted, scowling.

“I know,” she said softly. “But I’d like to help anyway.”

No one ever offered Sanemi help. They were too afraid of being snapped at, or worse. But she didn’t flinch when he barked at her, didn’t hesitate when he pulled away. She simply waited—patient, gentle, like sunlight warming cold stone.

That patience was her weapon. Slowly, painfully, she slipped past the walls Sanemi built around his heart.

He’d catch her humming sometimes in the garden, feeding the butterflies that fluttered around the wisteria. He’d pretend not to look, but he always did. Her laugh—quiet, genuine—was something he started to crave more than peace.

The Hashira meetings changed after that. Sanemi still snapped, still cursed, but sometimes his glare would soften when she was in the room. The others noticed. Giyuu had even smirked once, earning himself a fist to the jaw.

But it wasn’t until one night, during a mission gone wrong, that he finally understood what she meant to him.

She’d gone missing after a demon ambush. When they found her, she was kneeling in the mud, her sword broken, blood staining her sleeve—but still alive. Sanemi didn’t remember dropping his weapon or shouting her name. He only remembered the sheer terror of seeing her hurt.

She looked up at him, weak but smiling. He came.

“This is why you shouldn’t do this on your own…” His hands trembled as he lifted her, his voice breaking. “Don’t ever do that again.”

He was shaking. Two other Hashira watched.

He caught her hand in his and pressed it to his chest while tears streamed from his eyes. He never cried. “’Cause I can’t lose you..”

After that night, Sanemi was still Sanemi—loud, scarred, angry at the world—but there was a quietness in him now when she was near. She’d talk, and he’d listen. She’d smile, and he’d only think about her.