A/N: Written for the Kurtbastian Hiatus Project 'soulmate AU'. I love the idea that soulmates can cross borders, that not every human has a human soulmate. In this story, Sebastian is a seraph. Warning for bondage, minor blood, and minor burns.
Kurt slumps in on himself as his strength begins to give out, the shackles around his wrists pulling tight with the weight of his body as it sags, chains rattling as his knees bend and try to reach the floor. Kurt knows he is watching, his eyes fixed on Kurt's every move, but Kurt won't give the demon the satisfaction of surrendering.
Kurt is not weak.
"Just say the words and I'll let you out of the chains, my precious," Sebastian purrs, running his serpentine tongue over the back of Kurt's neck, lapping up beads of sweat like they're the sweetest wine, leaving a searing string of acid behind. "Say that you won't run away again."
Kurt throws his head back when another swipe of Sebastian's tongue burns his already scarred skin.
"I have no reason to stay," Kurt says boldly, knowing he will only further incur the seraph's wrath.
"Yes, you do," Sebastian hisses, running one long, exceedingly sharp nail down Kurt's bare back, slicing through the skin cleanly, leaving a narrow river of blood in its wake. "I am your reason to stay."
"You?" Kurt laughs, his voice weak but his tone wicked. "What the fuck would I want with a wretched, disgusting thing like you? I can't take you to dinner at The Four Seasons. I can't be seen with you during Fashion Week. You are nothing to me. Why don't you stop being so fucking pathetic and let me go?"
The seraph roars into the air, opening his leathery wings and beating them once in frustration at the puny human that dares defy him. If Kurt were anyone else, any other weak, spineless sack of blood and meat, Sebastian would simply tear him to shreds, slowly savoring his screams of agony, his whimpers, his begging…but he can't.
Kurt isn't just any useless human.
Kurt, as bizarre as fate may have it, is the one being made for Sebastian – the one who can make Sebastian whole.
"I am your soulmate," Sebastian says matter-of-factly, leaving no room for argument. "You are the one who has brought back the color to my life. You are the one I've spent all these long years searching for."
"Well, the colors haven't returned to my life," Kurt argues, sucking a breath through his teeth when Sebastian runs another nail down his back, leaving another thin river of blood behind. "I think you've got the wrong person. So let me go."
Sebastian beats his wings again, whipping the wind around Kurt with the fury of a hurricane. A wall of air hits Kurt full force and succeeds in bringing him to his knees. Kurt cries out in pain…but not entirely pain, which Sebastian would see for himself if he were looking into Kurt's blown eyes – large void pupils pushing away the last remnants of his ice blue irises.
"You will not leave until you tell me you love me," Sebastian growls, disgusted with himself for needing this human so badly, for desiring him, for wanting to wrap Kurt up in his wings and hold him close…to beg Kurt for the pleasure that Sebastian has denied himself for centuries.
"Fuck you," Kurt says, a blended snarl of grunts and grinding teeth, a sign for Sebastian that the beast may have managed to get Kurt to kneel, but that didn't mean he was going to give in.
Sebastian lunges forward and wraps a hand around Kurt's neck, digging the tips of long nails into pliant, white skin, almost losing his temper and slicing too deep, but an edge of sharp pain stabs Sebastian through what was once a stagnant heart – a heart that had begun to beat once again – and Sebastian recoils. He cannot bring harm to his soulmate. That would result in a pain even Sebastian would never be able to inflict…or recover from.
"I can wait," Sebastian says as he retracts his claws and prepares to leave. "I am a patient demon. I can wait."
Sebastian backs out of the room, taking one last look at Kurt kneeling on the dusty wooden floor. Sebastian's heart aches with how he longs for Kurt to accept him. If Kurt gave him any indication – one smile, one word of affection, one kiss - then he would unchain Kurt, lift him up from these shackles and treat him like the prince he is.
But that day is not this day, and Sebastian storms away to unleash his anger elsewhere.
Kurt hears the monster's feet retreat into the darkness and smiles. Everything is going exactly the way he foresaw it. All those nights he spent dreaming of the one. All those daydreams that occupied his mind so vividly that he couldn't concentrate on anything except him – the creature with the gem-like green irises surrounding glowing red pupils, scaled skin, and that voice – a gravelly combination of death and menace with a soothing undertone of velvet. The moment he walked into Kurt's life, every color of the rainbow had blossomed in his mind, and a few others he could have never imagined as well.
Kurt tries to rise, but he falls back to his knees. He thinks about the cuts along his back, Sebastian's tongue on his skin, his hand around his neck, and he smiles.
Yes, Sebastian definitely is Kurt's soulmate.
That doesn't mean that Kurt has to make things easy on him.