Prompt: Jack Frost!Toushirou falls in love with a sickly girl named Karin who loves winter even though she's not allowed outside so he brings winter to her.

On the ice stained window, luminous fernlike patterns glow. They look like they've been sprinkled in fairy dust when her fingers try to touch them from inside. Lazily, they unwind into new pathways, twisting and coiling away from the feverish warmth of her hand.

The sight makes her smile, the cool touch of glass soothing.

He's here.

"Come out, Jack Frost." Karin whispers, voice hushed in case anyone hears hers, trying not to sneeze. Her nose wrinkles, twitching, and before she realizes what she's doing, her head is resting against the cold windowpane, eyelids closing momentarily, greedily absorbing the cold, cold surface. "I know you're there, Toushirou."

"Aren't you going to invite me in?" His teasing voice says, and her eyes flicker open, and the familiar sight of him makes her feel better already. There he is, reclining on the other side, two icy blue eyes watching her, messy hair flecked in snow, and a quiet smirk that never truly leaves his face. "Did you think I'd forget?"

"No." Karin denies, heat rushing to her already too hot face, and sniffs louder than she means to.

Concern flutters over him, creasing the edges of his smirk into a frown, and the distance between them narrows as he tries to take a closer look at her through the window. "You don't look too good."

"'m not." Karin mumbles, grumbling as she struggles to think of words that make sense that don't include pulling the blanket around her closer. She tries to explain again, shrugging feebly. "Sick."

Her head returns to that old state of fuzziness, and Karin blinks blearily, static filling her mind until she tries to focus on the sound of his voice and listen. But for now, while her mind is emptying and muddled, she memorizes the details on his face, the snowflakes that could be mistaken for pale freckles and longs to touch them.

She was going to do something. Tell him something. Right?

Toushirou snorts. "Go to sleep, Kurosaki."

"Karin." She corrects, crossly, her anger an anchor that grounds her, however slightly. "It's Karin."

That was it. She wanted to open the window to let him in. They'd made a promise, after all. Hadn't they?

"Go to sleep, Karin." He says in a kinder voice, gentler than she is used to.

"Don't want to." Stubbornly Karin resists her sleepiness, but it's not enough to stop her words from being slurred. Somehow, she musters enough strength to push the window up. Only a little bit. But it's enough. It has to be enough. "Want to hang out with you."

There's a fondness on his face that she can't describe, and it sends warmth rushing through her chest that anyone else would mistake it for her fever. He manages to push the window the rest of the way up so he can climb through, and Karin inhales happily, breathing in the cold winds of winter.

"Let's get you to bed." Toushirou says, exhaling a cool breeze on her neck, and Karin leans into him as he all but carries her back to her bed, shivering and snuffling closer even though she hears him muttering his worries that she shouldn't. She'll get worse, not better, at this rate. Karin doesn't care.

His touch drains her dry, but Karin will never shield herself from him. She is too in love with ice and snow and the tales of winter that he brings; from across the world and the corner of the street to ever turn him away. She waits for him to leave fernlike patterns on her floor and glass windows and grins so much that her cheeks hurt when he does. She watches him in delight as he makes it snow in her room, and brush it away like dust dissolving in light, and she falls in love with him in the quiet moments when he smiles and becomes her friend. Karin waits for him to bring the winter to her.

He is cold as ice, and her eyelids are drooping. It's so hard to stay awake.

"You're staying, right?" Karin asks softly, reaching out for him as he leaves her, his cold hands comforting and perfect in between her fingers.

"Yeah." Toushirou agrees absently, careful not to disappear out of her line of vision. "I'm just closing the window."

"'kay." Karin yawns, struggling against tiredness, her thoughts melting into the cushiony pillow. "I thought…"

"I'm not leaving you. Not tonight." He says, scattering snowflakes on the walls; illuminated and white and pretty like crystals, and Karin wishes she was more awake to see this, to remember this more than some half-faded dream.

Last winter, they'd built snowmen together, decorated them with carrots and black buttons, hats and scarves, other adornments that was how tradition dictates the short life of snowmen that Karin liked to celebrate. Sticks for arms. Pebbled smiles. Those things. She was well enough then. Better than she had been in a while.

This year, Toushirou had promised to teach her how to ice skate. Promised that he'd leave winter roses at her window.

And then she'd gotten sick.

"You'll get better if you sleep." He tells her with the patience of a saint, the icy fingers carding through her hair, and the palm of his hand stills against the back of her neck, and Karin relaxes into his cold touch, succumbing to sleep at last. She barely hears him when he speaks again, too far gone. "I'll promise to wake you up before I go."

She thinks she smiles at those words, before she drifts, but she can't be sure.

But Toushirou is there when Karin wakes up; shaking her gently awake, ice cold breath making her cheeks tinge pink as she opens her eyes sluggishly.

"How are you feeling?" He says gruffly, cold hands like ice splayed around her shoulders. If he pushed, increasing the pressure only slightly, a careful press of fingertips against her delicate skin, just a bit more, he could bruise her. Fern frost would blemish her skin like faded scars, and he would never realize because she would never admit how much she liked the marks winter left behind. And yet, his touch becomes feather light, as if he realizes this about her anyway.

"Better." Karin replies, though she doesn't feel it. Toushirou doesn't look convinced, eyebrows furrowing in that suspicious manner that means he doesn't believe her but he won't say a word.

"You're shivering." He frowns, and Karin coughs, trying to pull her blanket closer and sit up at the same time.

"I'll be fine." She says, determined to see their promise through. "I want to do this."

"Okay." Toushirou gives in, and picks her up so they can see the sunrise from the rooftop. He's surprisingly strong, and Karin clings to the winter chill that his body radiates. She closes her eyes and sighs, trying not to tremble as her arms slide around his neck and his slide around her waist.

He is so cold and Karin cannot help but shake in winter's embrace.

Sometimes she is certain that he carries ice and snow in his pockets, it has to be the only reason that he is so cold. Besides being Jack Frost. He draws back, after she has settled on the roof, never out of reach, and tells her sternly. "But if I think for even a second—"

"Alright. Fine." Karin agrees carelessly, quickly interrupting. Then she yawns, still tired, not quite awake yet. She tucks her knees against her chest, toes curling, desperate to have this secret act of rebellion. "This is my only chance. And I want you here. With me."

"I already said I'd take care of you. Just. Don't make me worry." He grumbles under his breath, nudging her shoulder with his. "There's no other place I'd rather be, Karin."

She leans against him, and it's perfect. Her tousled locks of hair fall past his shoulder, catching snowflakes that seep into her skin, and she shivers. Tries to tell herself that it's just the cold that makes her heart beat faster, that makes her limbs feel weaker today, that she'll get better soon, and nearly believes it. His ice cold mouth kisses her warm forehead. "Next year, I'll teach you how to skate."

"Yeah." Karin grins sleepily at him, just as the sky begins to change; soft colours of yellow and orange streaking across the sky like messy fingerprint paintings that should be silhouetted with snowball fights late at night. She savours this moment she has with him with what little time she has left, and watches dawn with Toushirou by her side, happier still when he pulls her closer, the sky a pale pallor of pink. "I'll be looking forward to that."

"Until then." He says, his smile as soft as chalk. It sends an ache through her far worse than any illness that Karin has ever suffered.

Karin would be lucky if she could survive another winter. But she could survive today's beautiful sunrise.