Title: Listen to Your Instincts

Author: The Emcee

Pairing: Cor/Prompto

Rating: MA for sexual content and underage sex

Summary: Cor took Prompto in when he was eight, having found the boy among a pile of bodies and debris while on a mission in Niflheim. Now, eight years later and after resisting his alpha urges to take his adopted omega son, Cor's will finally dissolves.

Disclaimer: I don't own any of the characters or the fandom.

A/N: This pairing, I feel, was going to happen eventually. It usually does in one way or another: the big, bad stoic tough guy and the happy-go-lucky, puppy-like guy. Personally, I just like pairing Prompto with almost anyone who could top him. I can't help it; he's my baby. Getting back to the story at hand, it's set in Omegaverse. For those of you who aren't familiar with it, Omegaverse is kink trope where characters of a story have biological roles based on a hierarchical system, like wolves. If you want to know more, Google it. Aside from this being male on male, it'll also have underage sex and incest? Does incest count if half of the part is adopted? Anyway, the point is, if you don't like any of those things, then click out of this. It's not like I'm forcing you to read it. If you do, please feel free to leave a comment in the towel section down below. Enjoy!

~…~

Listen to Your Instincts

~…~

Cor could remember the first time he had ever laid eyes on Prompto.

He was on a mission to Niflheim, before the country was crippled and all but dissolved. The war was reaching its end and the missions were becoming more dangerous, bloodier, more gruesome. Cor remembered being in one of the outer sectors of the capitol city; he remembered the burning buildings, the cries for help, the sounds of gunfire and explosions. And then, there he was.

Sitting beside the dead body of what Cor assumed was the caretaker of the destroyed orphanage, face, clothes, and body covered in dirt with tear streaks on his face, was Prompto. Even though it was quite obvious the caretaker was dead, he kept shaking her and shaking her, crying and sobbing. It wasn't the first time Cor had seen something like that. War wasn't pretty; war wasn't fair; it was brutal and harsh and cold. Yet when he saw eight year old Prompto shaking that woman's body, something in him compelled him forward, almost like an invisible chain was tugging him towards the kid.

Cor finished his mission and returned home with Prompto at his side, quiet despite his tears, unmoving despite the fact that he clung to Cor like a lifeline. Regis was surprised by his sudden, unusual act, and Cor couldn't say that he wasn't surprised himself. He had seen plenty of kids crying for their parents, for their siblings, for their friends, for whomever, and he hadn't gone to such lengths to help him.

There was just something about Prompto…

He almost laughed when he recalled the young blonde's reaction when he approached him. The kid, he thought, had gone into shock when Cor knelt down and gave him a cool, unfeeling gaze. It wasn't natural for him to show much emotion aside from irritation and annoyance. Only when he was with his closest friends did Cor let himself go, and even that was limited. So, when he asked Prompto, "What's your name?" he wasn't expecting to get any kind of response. After a minute of silence, he was surprised.

"P-Prompto….Ar-Argentum," was all the boy could manage. It was what Cor had asked and he told the kid his own name and what his intentions were. Prompto didn't resist and Cor was a bit perturbed by how much like a ragdoll the eight year old was.

It was a process getting Prompto into Lucis and getting him citizenship was even harder as there were no records of his birthparents. According to Prompto, he had lived his entire life in that orphanage; it was the only home he knew and now, it was gone.

Cor would be lying if he said things had been easy at first. It had been years since he had lived with someone and he had never taken care of a child. He was a general, a man of the military, and he knew nothing of children. How was he to know that Prompto didn't know how to make his own meals yet or that he was behind in his schooling? The only things Prompto did know that Cor didn't have to teach him were bathing and cleaning.

Eventually, Prompto became capable of cooking, and he ended up being better at it than Cor was. School got easier for him too and it was only half surprising that Prompto made friends with Noctis, Regis' son and Lucis' prince. Noctis was quiet and so was Prompto. At first, anyway. A few years after being adopted by Cor and living in Lucis, Prompto came out of his shell, turning back into the happy boy he used to be before war had taken his home.

Of course, that wasn't always a good thing. Prompto was easily excited and got carried away easily, which meant that he tended to cause trouble. There were plenty of times that Cor had been called to school because of his adopted son, but that too subsided into only minor mishaps here and there, perhaps in part because of Cor and his strict parenting. That was something that would never change: Cor would always be a general, a military man, an alpha.

What did change was his view on Prompto.

Before Prompto turned thirteen, Cor could honestly say that he cared for the blonde as though he were his own flesh and blood son. Though strict, he was also very protective of Prompto, which was one of the reasons why he had so few friends. Cor tended to scare off any of the other kids; Noctis, Gladiolus, and Ignis were the exceptions to the rule, of course. And though it was hard for him to outwardly show it, he loved Prompto. The kid had brought life and light into his usually repetitive and lonely life.

Once Prompto turned thirteen, Cor's perception of him changed.

It had always been clear to Cor that Prompto wasn't an alpha. There was no way in hell he was; the blonde was too scrawny and too submissive to be an alpha. Noctis, who was quiet and reserved, showed more alpha tendencies than Prompto did. As Prompto grew from the tiny boy he had been when Cor had found him into that awkward, ever growing body, he found himself pondering just how he'd could best help Prompto through his heats. Heats, he knew, were usually awful, especially for a young omega and especially if they lived with a free alpha, one who wasn't tied down by another omega or even a beta. Just thinking about it gave Cor a shiver; it wouldn't be pleasant for either one of them at first. Prompto would need suppressants, contraceptives, and to be taken care of during his heats and Cor hadn't had to take care of an omega ever. It would be difficult for both of them.

However, a mere few days after Prompto's thirteenth birthday, he went into heat and Cor wasn't prepared for it at all.

His eyes snapped open at five fifteen that morning and he was rock hard and aching, aching to find the omega that smelled so delectable and enticing and make him his own, and he moaned loudly. Cor had been around many omegas in his life and had been around many in heat and he had never reacted this strongly. Usually, he could ignore the heat and all that encompassed it, yet he found himself unable to do so and it wasn't until Cor's hand was wrapped around Prompto's door knob that his body froze and his brain started kicking in.

He realized that the omega he had been smelling, that he wanted to take, to claim, to fuck, to knot, was Prompto, his adopted son, his thirteen year old adopted son. Cor was thirty-seven; that was a twenty-four year difference. Not only that, but Prompto was his son.

Groaning, Cor pressed his head to the cool door and listened as Prompto shifted in his bed, panted loudly enough for Cor to hear, and moaned and gasped every single time he fucking moved. He couldn't say how long he stood there, listening, wanting to break the door down and relieve Prompto of his heat. Of all the battles Cor had ever participated in, that one was one of the hardest. Forcing himself away from Prompto's door was hard, in more ways than one, yet somehow he managed. The rest of the day sucked balls and Cor swore that he'd be better prepared next month.

If he had known then what he knew now, he would have thrown in the towel and surrendered to his instincts. Prompto's heats, even with the suppressants and all of the rest, were just as bad. Every month on the twentieth, Cor would wake up hard and itching for Prompto, every fiber in his being telling him to claim the omega and make him his own. Cor always wondered if Prompto could feel it just as bad as he did; that pull that lead him to Cor and only Cor. It was highly unusual for an omega to go into heat so early; they usually started having heats around sixteen or seventeen. But to start having heats at thirteen…that only happened if an omega's true mate, their destined partner, had been around them for quite some time.

That was a can of worms Cor would save for another day, far, far off into the future.

What it came down to was that Prompto's heats were unavoidable and awful, with each and every one dwindling away at his resolve and will-power with every month. And Cor had endured three years of them.

Now, Prompto was sixteen and his heats now were just as bad as they had been three years ago, three long and difficult years. Not because of Prompto himself; his boy had been amazing, getting good grades, mostly staying out of trouble, keeping the house clean while Cor was at work, and having dinner ready and waiting as soon as he came home. Almost everything Prompto did for him made Cor groan in frustration, sexual frustration. He was acting like they were mated already and it drove Cor insane. He wanted so desperately just to take Prompto during one of his heats, and he knew that he couldn't hold on for much longer.

Several times, Cor had almost opened Prompto's door and crept into his room while he was in heat. Even when he wasn't in heat, Cor would do inappropriate stuff. His touches would linger longer and have different meaning than they did before. His eyes would soak up Prompto's image and milk in the sight of him, down to the droplets of water he had failed to wipe off from his shower or how many freckles adorned his face. At night when the house was dark and quiet and still, Cor would envision what it would be like for Prompto to be asleep beside him, his smaller form cuddled up against his own, naked, ready for Cor to take whenever he pleased.

Groaning, Cor ran a hand over his face and looked over at the clock on his nightstand. Six am. He had been awake for two hours now, lying in bed, thinking of Prompto and how much he wanted to claim the omega. It was, of course, the twentieth and Cor could practically taste Prompto. That was how strong his heat was. There was no way for Cor to ignore it; it enveloped every one of his senses and drove him completely and utterly mad.

Three years. He had held strong for three years. He could hold on for longer. He was Cor Leonis, a general for Lucis, Head of the Royal Guards, the Immortal Shogun; he could accomplish anything.

Throwing his bed covers off of him, Cor rolled out of bed and made his way towards the kitchen. A cup of coffee would, hopefully, help. He had made it to Prompto's bedroom door when he stopped. As usual with every heat, Cor leaned his head against the door and listened, breathing in Prompto's scent as he heard the omega rustle and turn and moan and gasp. Just as he was about to turn and go, he heard something he had never heard before coming from Prompto's lips.

"Cor…"

Cor felt his dick twitch, his heart beat almost painfully in his chest, his eyes widen, and sweat trickle down the back of his neck.

His name coming from Prompto, a moan really, sounding so very sinful and heavenly, caused his hand to reach out, take hold of the door knob, and turn it. He opened the door with a little more strength than he meant to, but he didn't care. Cor's eyes were focused solely on Prompto, who was lying on his bed, his covers tangled around his ankles, and his body stripped of any clothing. Sweating, panting, and smelling entirely of sex and musk and everything Cor could ever want in a mate, he was irresistible.

Prompto's eyes widened only a fraction as he lifted his head up and took in Cor's form. The alpha knew he must look like a sight: his cock rock hard and obvious in his boxers, his chest rising and falling, sweat starting to coat his body, and his eyes clouded with lust and desire. All the blonde did in response was moan and close his eyes, one hand in his sweat slicked hair while the other trailed down his body. That brat, he knew what he was doing even if it was instinctual.

Cor crossed the space between them and watched as Prompto wrapped his hand around his leaking cock, stroking it slowly. His body arched slightly off of his bed and, with eyes boring into Cor's own, moaned. That was all the encouragement Cor needed.

He leaned down and smashed their lips together. Prompto's mouth opened to his tongue and he delved into that moist cavern, groaning at how delicious the omega tasted to him, better than any meal, better than anything he could think of. Thin arms wrapped themselves around his neck and pulled him down. Cor's hands dove into those soft, unruly blonde locks, fingers wrapping around the wet strands as he brought his legs up onto the bed, his knees incasing Prompto, preventing him from escaping.

Prompto arched up, trying to press their bodies together, but he couldn't. One of Cor's hands traveled down the blonde's back and lifted him up, pressing the smaller being to him and just that simple contact was enough to calm his inner turmoil. He broke their kiss and began a trail of them up and down Prompto's neck, licking, nipping, and biting at the pale flesh presented to him. Smaller fingers played with his short hair or gripped at his shoulders or ran up and down his back. It seemed as though Prompto couldn't get enough of him. Well, he wasn't the only one.

Cor pressed Prompto down onto the bed, more than covering the omega's with it. One arm wrapped around his waist while the other ran up and down his chest and stomach, stopping just shy of his cock, not touching it, not yet. He stopped kissing his neck and ran his nose up and down the abused flesh, stopping on his scent gland, inhaling the delicious scent that reminded him of caramel. Salty and sweet all at once.

His eyes lifted to Prompto's face briefly and he was pleased to see it flushed with heat and arousal, his hair clinging to his skin, and his eyes half lidded as he tried to rub his body against Cor's. Hard to do when the alpha weighed more than he did and was far stronger. Bending his head, Cor bit down on the juncture between Prompto's neck and his shoulder. Prompto arched up against him as much as he could, releasing a moan that could wake the dead, and came, coating both of their stomachs with his seed.

Smirking, Cor lifted himself up just enough to cradle Prompto's face in his hands. Despite not often being loving and affectionate, he hoped that the blonde knew when he was expressing himself, like right now, holding him so tenderly, so lovingly. Cor leaned down and kissed the omega. Prompto clung to him, in much the same way that he did eight years prior, and returned every kiss given. The hand that had been trailing up and down Prompto's torso traveled all the way down to wrap around his half hard cock. He pumped it once, twice, three times, four, until it was fully erect once again. Then, he went further.

One finger danced lightly around Prompto's slick entrance, letting the slickness coat his finger more than generously. He needed to prepare Prompto reasonably enough; Cor was a big man. As gently as he could, Cor inserted his finger into Prompto's tight heat, feeling around it, marveling at how hot he was, how wet he was, how utterly incredible he felt. Cor's lips left Prompto's and trailed down to his chest, where he kissed and licked. He felt Prompto's chest rise and fall with each pant. One hand gripped his muscled back while the other tugged at the short strands of his hair. As he took the blonde's left nipple into his mouth to suck, Cor curled the finger that was inside of him, the gasp that he got from it music to his ears.

Cor tugged at the nipple with his teeth and kept abusing it until he was satisfied that Prompto's voice could go no higher than it already was before moving to the right one. He pushed a second finger into his marvelous heat and began scissoring the omega, slowly at first, pulling them all of the way out until Prompto started whining and begging like a whore on the street before he plunged them back in. As he finger fucked the omega, he released the nipple he had been suckling on and silenced Prompto's cries with his mouth, his tongue entering him once more.

After adding a third finger and stretching Prompto as much as he could, Cor removed his fingers in favor of something much bigger and better. Lifting his body up and away from Prompto, Cor gazed down at the blonde. His right hand cupped his flushed cheek, his thumb caressing the skin there, before it traveled down his neck and then his side, resting on his hip as his light blue eyes drank in the sight before him.

How many times had he envisioned seeing Prompto like this, panting and flushed beneath him, his body slicked with sweat and some of his own seed, ready for the taking? How many nights had he lain in bed desiring to claim the omega as his own? How often had he tortured himself, forcing himself to stay away when all he wanted was Prompto?

Well, he was tired of staying away and denying himself what he wanted. He was tired from suffering these heats and of forcing Prompto to do the same. Regardless of how right or wrong this was, his instincts were telling him one thing and one thing only: claim his omega.

Gripping his dick in his hand, Cor lined himself up with Prompto's entrance and slowly, slowly eased his way in. He couldn't stop the loud, guttural moan that escaped him as his cock was engulfed by the wonderful heat and tightness. His eyes fluttered shut and Cor buried his face against Prompto's neck. After stilling for a moment, Cor realized that Prompto was pleading with him, begging for him to move, to take him, to fuck him well and good into his mattress. Such a brat. His brat.

Cor pulled out until just his tip remained in and he smirked against Prompto's neck.

"What do you want, Prompto?" he teased, his voice deep and full of lust and need. He could feel Prompto sag beneath him.

"Come oooooooon, Cor!" Prompto panted. "You know what I want!" Cor shook his head.

"No, I really don't. You're going to need to spell it out for me," he continued. Prompto shuddered and squirmed beneath him. He would have tried to fuck himself on Cor's cock, he knew, had their bodies not been pressed together.

"Coooooor…" Prompto whined. He sounded pitiful. Cor loved it.

"Tell me," Cor ordered him, all teasing gone from his voice.

"I want you to fuck me, damn it! Fuck me. Please, please, please take me! Give me your knot! Give me all of it! Just…please…" his pleading ended in a sob and Cor felt a pang of guilt for having pressed his omega so far. He pressed a kiss to Prompto's neck before he lifted himself up and pulled out entirely.

"Whaaaa?!" Prompto began but stopped when Cor flipped him over onto his stomach.

Pulling Prompto by his hips so his ass was raised in the air, Cor lined his cock up again and shoved himself inside without abandon. Prompto cried out and almost arched his back. Almost, because Cor pressed his chest to Prompto's back, mounting him properly for deep fucking, and began thrusting in and out. Etro, Prompto was so damn tight and hot. Hearing his moans and smelling his addictive scent was all Cor needed to lose himself in their mating.

He couldn't keep track of how hard or fast his thrusts were; all he could register was the feel of Prompto around him and the cries his dear omega made beneath him. Cor knew he was growling and grunting and moaning just as much and just as loudly, but he didn't care. Leaning down, Cor nuzzled Prompto's neck before he bit down again, marking the blonde as his once again.

All too soon, Cor could feel his knot emerging, spreading into Prompto's body before it took root and chained them together. He felt more than heard Prompto come onto his bed and that tipped him over the edge. Cor spilt his seed inside of Prompto, his small, shallow thrusts just what he needed to ride out his orgasm, his knot not letting him retract any further, not that he wanted to.

When he was finished, Cor leaned against Prompto's back, careful not to put all of his weight onto him. Not that that helped; Prompto collapsed beneath him anyway. Panting and slicked with sweat, Prompto blinked slowly as he came down from his own high. Cor could help but find him endearing and beautiful; he leaned down and kissed his cheek softly. Prompto smiled and tilted his head just so that their lips could meet. The kiss they shared was brief, but sweet and tender.

"It's…about…time," Prompto panted out after a few minutes of nothing but pants and the sound of sheets rustling.

"I had a feeling that you planned this, you little shit," Cor grunted. He couldn't help but smile just a little bit though. That was definitely something Prompto would do.

"Not my fault…you're so…fucking hot," Prompto replied.

"Watch your language, punk. You live under my roof, don't you?" Cor corrected him. Prompto huffed a laugh and gave him a tired smile.

"You're not gonna let up on me even though we're mated now, are you?" Cor arched an eyebrow at him.

"What do you think?" he asked. Prompto reached up and stroked his cheek lovingly.

"That you're lucky I love you or else I wouldn't have let you done that," Prompto said and then, he kissed him. Cor returned it and when they parted he buried his face against Prompto's neck.

"You're lucky I love you too, even if you are a brat," he said.

Prompto's soft, breathy laughter filled his ears and for the first time in three years, Cor felt normal, relaxed, and finely, truly at home.