Incubus Tony AU
Sex is less fun when it’s a diet.
Incubi are a myth, by the view of most people on the planet. In fact, most people think that the very idea is hilariously outdated, but fascinating.
Tony Stark wished he’d really looked into those myths sooner.
Having been born the same way anyone else was, he’d never really understood that there was anything weird about the way his father slept around, especially given that his mother clearly didn’t mind, and that had served as something of a role model. The man had rarely, if ever, gotten sick, and when he did, it was always increasingly worse until his mother spent a lot of time with him.
He just figured that it was because someone was putting all their focus into making him better.
Which was sort of true.
He just didn’t really understand what made it true until he was nearly fifteen, that was all. Apparently being a bit late to the puberty train was normal in the Stark family, and his case was no different. Of course, that didn’t make being absolutely tiny compared to his classmates, increasingly so as he failed to hit a growth spurt until college, of all things, any better. No, it made it considerably worse.
But when it came, it hit hard, and suddenly the bullies were a little less rough on him, and the girls a lot more interested.
He’d been baffled.
His dad called it charisma.
His mom called it inevitable.
Neither one called it what it was. Hormones. Ridiculously appealing hormones, apparently.
He was just grateful, after careful reading when he got older, that he wasn’t really like the stories. In fact, he hadn’t even realized that after his first… experience with sex, that he’d sort of hit an on switch somewhere inside himself that meant he’d always be hungry thereafter. He was too busy exploring and being a prodigy college student to really get it.
Which was both good and bad, because it meant that it wasn’t until years later, well into his adult life, that he really grasped that there was anything strange about him at all.
Sure, he’d never gotten sick, and he’d always recovered that hair faster than the people around him when he got hurt, but he figured that was just good genetics, like his intelligence.
He didn’t think anything of it when he was horribly weak and sick in the cave, guessing it was the torture and poor conditions doing it, to say nothing of the magnet in his chest.
He didn’t think anything of it that his complete lack of sexual contact, once he had the reactor, was a new factor he needed to take into account.
It was after the Palladium was fixed, with Pepper, that something finally changed. He’d never actually had a consistent partner before her, so he’d never really noticed any kind of side benefits of sex. If he was honest, their honeymoon phase didn’t really change that either, and she certainly seemed energetic enough to distract him from scientific thinking. In fact, their relationship made him feel better than he had in years, at that point, but he attributed that to the new element in his chest and the fact that he was happy. He didn’t know that having a solid partner, partners really, made any kind of difference to his biology.
Right up until the next time he got hurt in the armor, and he healed.
Fast enough to notice it.
Fast enough Pepper definitely noticed it.
And neither of them had a clue what could have caused it, because it was new, strange, and definitely not the element in his chest like he’d thought was the case because of the poison.
It wasn’t until they were separated for long periods of time after they got together that it really became a thing though, with Tony in New York and Pepper in Malibu. That was when he got sick again, like he had after Afghanistan, minus the bout of poisoning that he’d been blaming it all on the first time.
In fact, he went so far as checking for poison, it was so unusual, and the healing, speedy as it had been for a while, was back down to rather normal sluggish levels. Which led to a series of tests that left him with one rather hilarious conclusion.
If he didn’t have sex, he got sick. He got weak. If he did have sex, well, he had to confirm it, but apparently, if he had sex, he felt better, and if he had a lot of repeat sex, he felt even better than that.
…He had no idea how to break this to his teammates, but he suspected that they really needed to know. Accelerated healing, after all, was nothing to sneeze at, and he had no idea what other benefits he got from it yet, and sort of wanted to know.
Details on the biology:
He puts out hormones that either aggravate or interest the people around him. Sometimes at once even. It’s subtle and doesn’t actually control anyone in any way.
Regular partners, this can be more than one, sort of add more to his pool of energy because his body will come to recognize their ‘signature’ of sorts and sync enough that he can take more from them. This doesn’t have adverse repercussions save making the partner tired, and that’s easily slept off. This is why he heals more quickly with a regular partner, and that would increase dramatically if he had multiple partners, not that he’s actually aware of this.
One night stands are like snacks, enough said.
Kisses and cuddling can have similar, if lower key effects to ease off the sick feeling that happens when he goes without. It means he’s nearly perpetually at least a little touch starved.
The element in his chest actually filters on the same energy frequency as Tony’s default feed state, which is why he got such a boost from it. It’s not sustainable, however, and is the equivalent of trying to survive on candy.
The gene is only inheritable through the male side of the family, and his type of quirk is not the only one along these lines out there. He’s just the only one he knows about.