Arch-Nemesis (SakuAtsu Dystopian/Meta-Human AU)

14

"For a second, I really thought ya were gonna kill me, y'know, Omi-kun?" Atsumu mumbled.

Kiyoomi merely chuckled, continuing to run the fingers of his freehand through Atsumu's soft hair.

There were in Kiyoomi's room, lying among a mess of sheets and blankets. Atsumu rested his head on Kiyoomi's chest, their hands entwined.

Atsumu listened to Kiyoomi's steady heartbeat. It was calming.

"Why would I do that?" Kiyoomi asked, his chest rumbling as he spoke, "We're on the same side now."

Atsumu shrugged, "Ya could've been a spy."

Kiyoomi rolled his eyes, "So, you'd sleep with a spy?"

Atsumu squeaked in indignation, "Hey, yer the one who walked up to me all inverted, lookin' like ya'd lost yer marbles, an' then proceeded to fuck me within an inch of my life."

Kiyoomi grinned, "So, you did enjoy it," he teased.

Kiyoomi didn't even have to look at Atsumu to know that he was flushed down to his chest.

Atsumu sighed, "'Course I did," he grumbled.

Kiyoomi frowned, "You don't sound very happy about it," he pointed out.

"Well, my back is officially broken," Atsumu countered, and Kiyoomi couldn't suppress his snicker, "But that's not the reason... I jus'- What does this mean for us?"

Kiyoomi hummed, "It seems we've placed ourselves in quite the complicated predicament, haven't we?"

"Haven't we always been in a complicated predicament?" Atsumu countered.

Kiyoomi blinked, "Good point. I take it you've noticed the effect you have on me, then? If you didn't see it before then you definitely do now."

Atsumu was quiet for a moment, "Which one? The fact that I calm yer negative energy rage, or the fact that yer heart starts racin' whenever we're in the same vicinity?" He asked.

Kiyoomi clicked his tongue, "So, you did notice?"

Atsumu hummed, "I chalked the heart rate up to adrenaline, but then the others told me 'bout ya protecting me while inverted. Piece all that t'gether with last night, when ya kissed me an' immediately reverted, I surmised a few things."

"Those pesky blood powers of yours are always giving me away, I swear," Kiyoomi sighed.

Atsumu laughed, "Well, yer stuck with 'em now, Omi. I ain't goin' anywhere."

"I take it you're sticking to 'Omi' then, huh?" Kiyoomi questioned and chuckled when he felt Atsumu stiffen.

A dark red blush bloomed across Atsumu's face. The nickname had slipped after he'd called Kiyoomi that all night.

Suddenly, Atsumu was flat on his back with both his hands pinned above his head by one of Kiyoomi's. The grip was loose enough so that Atsumu could pull free if he wanted to, but the blonde really, really didn't want to. Obsidian-green eyes locked onto honey-brown, amused. Kiyoomi, kneeling between Atsumu's legs, hovered over the blonde. He dragged his free hand up the inner side of Atsumu's thigh, over all the old burn scars and fresh bite marks.

"It's okay if you call me that, Atsu," Kiyoomi said quietly, causing Atsumu to burn bright red, "Only you can, though," he declared.

Atsumu nodded frantically. Kiyoomi's dark gaze seemed to devour him wholly.

A dark chuckle escaped Kiyoomi's lips, "I knew I had the same effect on you as you have on me," he whispered.

Two hours later and Kiyoomi was in the training room. Sweat ran down his back and dripped from his forehead. He was practicing his kicks and punches against a standing punching bag. Meanwhile, Atsumu watched from the windowsill.

Kiyoomi delivered a powerful kick to the bag. It had been a while since he fought like this. It felt natural to imbue his negative energy into his attacks. He was trained in muay thai when he first joined the Adlers, but shortly after, he was given the power dampening guns. He never did much hand-to-hand combat after that, especially since Atsumu used to keep his distance whenever battling Kiyoomi to avoid getting hit with the negative energy.

Muay thai was already dangerous by itself, but with Kiyoomi's negative energy added into the mix, it was downright lethal. He delivered another powerful kick and the bag went crashing to the ground. Kiyoomi hunched over, hands on his knees as he blinked rapidly.

His eyes flickered between their regular state and their inversion state. Atsumu slipped off the windowsill and made his way over. He crouched in front of Kiyoomi, gazing into his flickering eyes. Atsumu smiled softly and Kiyoomi's eyes reverted to their normal state and stayed that way.

"Damn," Kiyoomi muttered as he swiped his forearm across his forehead, "Controlling it is going to be way more difficult than I thought..."

Atsumu hummed, "Yer learnin' to catch the signs, though. That's some progress," he pointed out before walking back over to the windowsill.

He grabbed the towel that was on the windowsill and tossed it at Kiyoomi. He watched carefully as Kiyoomi dried the sweat on his face and the back of his neck. He'd let his eyes drift a bit too far when Kiyoomi's voice snapped him from his thoughts.

"You know, I might learn quicker if I had a sparring partner," he drawled.

Atsumu rolled his eyes, "Not happenin'."

Kiyoomi sighed, "Remind me why not again."

Atsumu smiled mischievously, "'Cause one, my back is killin' me right now, an' two, I'm not in the mood to be burned with yer negative energy," he listed off on his fingers.

Kiyoomi rolled his eyes, "You said you're well-versed in most weapons, so pick one that will allow you to not be hit."

Atsumu snorted, "Sure, an' what do I do 'bout the fact that I am in pain, 'cause of ya, might I add?" He countered.

"You've fought me in pain before," Kiyoomi smirked, "And you'd better get used to it."

The blush that flooded Atsumu's face was enough for Kiyoomi to start laughing.

Atsumu grumbled a few cursed under his breath before he sighed and pushed off of the windowsill. He gingerly walked over to the weapons rack. He picked out a long metal quarterstaff and moved over to stand directly in front of Kiyoomi.

Atsumu reached up and grabbed Kiyoomi's chin. He tilted Kiyoomi's head down to gaze into his eyes. He sensed the increase in Kiyoomi's heart rate and watched his eyes momentarily invert and then revert.

Atsumu narrowed his eyes, "Ya'd better make up for this tonight," he warned.

Atsumu smirked when Kiyoomi's eyes fully inverted and stayed that way for a good few seconds before he blinked and they were back to normal. Kiyoomi's hand closed around Atsumu's and used it to pull him close.

"You know, you're a real pain in the ass," he said lowly.

Atsumu grinned, "Look who's talkin'," he countered.

Kiyoomi chuckled and stepped back, letting go of Atsumu's hand. He got into a fighting stance and Atsumu followed suit. After a short breath, Kiyoomi attacked.

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I like to think of this part of their relationship as 'frienemies with benefits'

Anygays! Bye!!
-CrackshotReaper

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