#1 Reason Not to Mate With Humans

Winner of the Term 2d Fic Poll! The winner was 'KiriDeku Fantasy AU Oviposition'. This...this wound up a little more angsty than originally planned, complete opposite of last time but honestly...I really like this one <3

WARNING! This fic contains mentions of blood and injuries, specifically bites and cuts! 

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It…it honestly was an accident. He’d been so caught up in the fun he was having with Izuku, he just sort of forgot how close he was to his species equivalent of a ‘heat’. Normally, when he realized it was time, he really only had two options: endure it alone or find another of his species who was willing to take his eggs. He’d only endured two heats so far – both being spent by himself, tortured by the weight of his eggs and crushed by the desire to impregnate anyone, it didn’t who or what. He got through both no worse for wear…but still with no endurance built up. No, it usually took his species ten to fifteen heats spent alone to build up an endurance. Those who hadn’t…well, it wasn’t advised to be around anyone when they went into heat. Doing so lead to…complications. He had never really understood what the others meant by that but had always done his best to heed their warnings. Despite not fully understanding it, he could, at least, get that it wasn’t a good thing to be around someone else (especially someone he liked) when he went into heat. 

Another thing he was warned about was never losing track of his heat. That one he could understand, and it was one he chose to completely disregard as he followed Izuku through the forest, both of them keeping a close eye out for a special plant Izuku was looking for. He assumed he still had a couple of days. 

…he was wrong. And now, he understood why the others always told him to be careful, that it wasn’t good if he was with someone when he went into heat. 

Panting raggedly, his vision somehow both wildly flickering and unwaveringly focused on Izuku, sweat rolling fat droplets down his face, back and chest, Kirishima clamped down tightly onto Izuku’s thin hips, so wrapped up in how good it felt to have both his cocks buried deep inside his wet, hot hole to care that his sharp nails digging into Izuku’s smooth, warm skin, leaving ten gouges that swelled and coursed with blood. Sobbing weakly, his expression dazed and distant, Izuku bounced listlessly in his hold. His face was flushed bright red. His mouth hung open, tongue lolling lewdly. Tears coursed down his cheeks. Blood ran in thin streams from the scratches and slices that Kirishima’s claws had left. All over Izuku’s right shoulder was a heavy mess of congealed blood, which partially obscured the jagged bite mark Kirishima had left. That…that right there had been the beginning of all this. He…he hadn’t meant to. He hadn’t meant to bite him but when his shirt ripped, revealing the gentle slope of his shoulder…he…he just couldn’t control himself. Izuku…he was too cute-! He was too godsdamn cute-! 

And now…he was even cuter with his stomach swollen full with Kirishima’s eggs. A hard shudder wracked Kirishima’s body. There were still so many left, so many waiting to be welcomed into the warmth of Izuku’s body…but his belly was already so full. Kirishima could practically see the shapes of his eggs inside of Izuku. The sight…it was the most beautiful thing he’d ever seen. Izuku…he was so beautiful! Smiling shakily, Kirshima slid one hand up to gently press it to Izuku’s engorged stomach. Izuku moaned weakly, his thin body trembling. His plump, erect cock (Kirishima’s gaze flickered down to stare shamelessly at it, a sizzle of heat radiating up his spine – so small, so plump! Were all humans cocks this adorable or was it just Izuku’s?) twitched, a spurt of precum dribbling out of the slit. Despite Izuku’s initial resistance, it had been so easy to make him cum. Even when he was crying from the pain of being bitten, forcibly stretched open by Kirishima’s two large, ribbed cocks, and stuffed full of his eggs, he kept cumming until semen as clear as water was coming out of his cock. 

It was obvious that he wasn’t going to last much longer. Kirishima supposed this was another reason why mating with humans was strongly advised against. Their stamina, their endurance was nothing in comparison to his species. He was lucky that Izuku, despite his small stature, was so durable! Grinning dizzily, love and fondness blooming in a great blossom of warmth in the center of his chest, Kirishima reached up to swipe the pad of his thumb over Izuku’s scalding hot cheek. It was regrettable…having to stop here but it was what was best for his adorable Izuku. He…he had already been so rough with him. So…so terribly rough. Unnecessarily rough. Why…why had he hurt him so much? He…he loved Izuku, why had he…He…A sharp bolt of cold stabbed through his chest. All the heat, the pleasure was gone in an instant. Dragging in a choked breath, Kirishima’s stare frantically darted all over Izuku’s body, taking in the horrific condition he was in. 

“K…Kir…Kirishi…ma-kun…” Izuku whimpered, “P…pl-please…”

He was moving without thought, pulling Izuku off his steadily softening cocks. Panting erratically, violently trembling with horror and terror, Kirishima carefully lowered Izuku down onto the forest floor. What…what had he done?! Why had he-?! Tears streamed down his cheeks. A lump rose up in the back of his throat. His lungs were seizing. Scrambling forward, Kirishima forcibly retracted his claws so he could cup Izuku’s cheeks without hurting him. Godsfuck! How could he have done this to his Izuku?! Humans couldn’t handle being impregnated with Dragon eggs! He…he needed to get Izuku into town immediately to get these damn things out of him!

“I’m sorry-!” Kirishima cried, his chest heaving with harsh sobs, “I’m sorry-! I’m sorry-! Iz…Izuku! I’m so sorry! Hang on, I’ll get you back to town! It’s gonna be okay-! I-! I-!”

Trembling fingers brushed against his cheek. Kirishima gasped sharply. Izuku looked up at him with a slight smile, his eyes almost closed, “T…thank goodness…you…you’ve come back to your senses…”

“Izuku…” Kirishima whispered, his bottom lip quivering, “I’m sorry-! I’m sorry, Izuku. I’m so sorry. I’m-!”

Izuku slowly shook his head, “It…it’s okay…know you didn’t…mean too…”

“Still-! Still-!”

“Kiris..hima-kun…lo…love you too…That’s why…right…?”

Kirishima’s eyes widened. All the breath rushed out of his lungs. Fresh, scalding tears welled up in the corner of his eyes. Face screwing up, Kirishima sobbed bitterly. Gently pushing his fingers through Izuku’s sweat soaked hair, he slowly leaned down to press a kiss to his lips. Izuku weakly moved against him, returning the kiss as best he could. 

“Yeah…love…I love you, Izuku…”

“I’m glad…” Izuku giggled weakly, “I…I wanna go home…Kir…shima-kun…”

Izuku’s voice was becoming weaker and weaker. Kirishima straightened up, his stomach lurching with a sickening thump. All the color was gone from Izuku’s freckled face. His eyes were closed. For one sickening moment, Kirishima thought for sure that his book had closed but no…he was breathing! Breathing…still visibly breathing but he couldn’t afford to waste any more time! He needed to get Izuku to a medic immediately. Gathering Izuku’s limp body up into his arms, repeatedly whispering ‘I’m sorry’, Kirishima took off in the direction of the town. He…he might be exiled for this but that didn’t matter. All that mattered was making sure that Izuku…his Izuku was alright!