"Amaimon offers Mephisto a wager: Teach Rin proper demon etiquette and in return Amaimon gets to play with him and Mephisto will finally go back to Gehenna where he belongs. What actually ends up happening is: Rin teaches Amaimon human things, Amaimon sort of loses the bet and stays in Assiah. He finds he doesn't mind in the end."

"Set around chapters 39-44, pre Shura leaving, the festival, Mephisto's tests, and the rescue-Izumo arc. Post the impure king arc, Shura/Rin/Shiemi suspecting Yukio is hiding something (his eyes and the interaction/fight with Toudo) and Rin failing to get him to talk about it."

"Alternatively, Amaimon wants to bring out the demon in Rin and get Mephisto to come back to Gehenna with him, Mephisto just wants Rin.

A/N So I should be working on Retrospective Days but my current obsession with AoE won't leave me alone, especially since there's so little material to mindlessly consume and I've already gone through all the fics involving either Amaimon, Mephisto, Rin or any combo thereof (can you tell I have a character type? I have a character type. It's demons).

Well, there's only so many times I can re-read Opalescent by PresidentGuppy on ao3 (actually that's a lie, that fic is my fav in this fandom and also definitely makes my top 10 favorite fics of all time in any fandom so uh make that infinite times I can read that fic tbqh :P).

So, here's my guilty pleasure one-shot, with a multi-chapter yyh/aoe crossover planned for the future bc when have I ever written for a fandom when I couldn't also cross it over with yyh? lololol

"Brother."

Mephisto gave no notice that he'd heard the weak voice coming out of the darkness, letting the speaker stew in silence until he'd made his point.

He could practically feel the glare leveled at his back.

"Have you calmed your murderous intent towards our little brother, yet?"

The elder demon finally turned his attention to the body held aloft on cruel spears as he awaited the other's answer to his question.

Amaimon stared at him with his usual impassive expression, ignoring the rivulets of dried blood that had darkened his green hair into a sticky mat around his face and left flaking trails beneath his bruised eyes.

He'd taken to licking off the blood that he kept coughing up, a poor substitute for the sweet suckers and candies the earth king preferred.

"Yes, brother. But-"

Mephisto arched a brow, patiently letting the other make his point. Amaimon wasn't the type to display his inner thoughts for all to see. Not to say that he was shy about stating what he thought, but he took time to chew things over before speaking his conclusions- at least when he wasn't in a blinding rage.

Mephisto never relied on anyone but he did enjoy some of the insights his favored brother could come up with.

"I can't understand why you coddle him so much," Amaimon shrugged, a few more drops of fresh blood escaped from the edges of the holes caused by the spears, spilling over the congealed old blood that had sealed them closed.

Mephisto had noted that Amaimon would occasionally re-open the wounds himself, the pain giving him something to do while he was in his time out. His younger brother was a bit of a masochist when he was bored.

"And," Amaimon continued, scrunching his eyebrows, the only sign of the confusion he was feeling, "I can't understand why you and father are so entranced with him. He is so weak and oblivious, especially about his demonic nature, that it hurts to watch him."

Mephisto snickered at his poor brother's confusion, not that he would be fully letting on what his plans were for Rin to the other just yet, "you'll just have to keep watching him then, if you don't understand. And refrain from trying to kill him, please."

That brought a scowl from Amaimon and the demon let out an angry mutter that Mephisto caught but, proper etiquette required he press his impertinent brother to speak up.

"I said," Amaimon pouted, eyes shifting to look away from Mephisto, "I just wanted to play with him, not kill him."

Mephisto outright laughed at that, leave it to his brother to say something so ridiculous.

"My dear Amaimon, I'm afraid your- affections, may be a little much for our Rin at the moment."

Amaimon absently licked at the blood staining his fangs, contemplating his brother's words before he responded, "so, when will Rin be ready for me to play with?"

Mephisto hummed, bringing his hand up to hide his satisfied smile, "your brother may have misunderstood your intentions and certainly isn't ready for your level of play just yet."

"It's as you've said, Rin is woefully lacking in demon etiquette," Mephisto shrugged, "never mind his atrocious manners as a human."

Amaimon ignored the grumbled last bit from his older brother, eyes widening in interest at the first half.

"If I teach him etiquette will you let me play with him?" Amaimon looked as if he'd love to be chewing one of his long claws as he mulled over his brother's words. Some new blood welled up along his pinned arm as he tried to move it towards his mouth, "And you'll come home with me to Gehenna then, right?"

"Is that a wager, Amaimon?" Mephisto drawled, watching with acid green eyes and a smirk that pierced his brother as surely as the spears did.

Amaimon tilted his head, noticing the rapt attention the elder demon was suddenly paying him.

A vicious, toothy smile lit up his pale face, gold eyes seeming to glow in their intensity, looking macabre in the darkness of his brother's prison.

"Yes."

Mephisto snapped his fingers and Amaimon found himself freed from the spears holding him up.

They were back in Mephisto's office at the True Cross Academy.

"Clean yourself up, it's impossible to get the blood stains out of this carpet and I have a summons to attend to."

Amaimon felt holes closing that the spears had held open in his body for, well, it was always hard to tell how long when his brother could mess with time like it was a toy.

The earth king hauled his aching body up carefully, still not fully in control of his movements as ligaments and flesh knit back together. He could definitely do with a shower before he began the hunt for Rin.

Probably best not to say that last bit out loud, Amaimon reflected. He didn't need Mephisto hearing him think about his task as some sort of target he was hunting down for sport. His brother was weirdly enamored with the half-breed.

Still, best get this over and done with as soon as he could. The earth king was growing impatient waiting for Mephisto to tire of Assiah and come home with him.

He stopped at the door, turning back to Mephisto.

"Ah, brother-"

Mephisto looked up from the things he'd already begun gathering to leave with, "yes?"

He smiled then, realizing what the other wanted.

"Of course, you don't deserve this but you have given me an interesting bet, so-"

Mephisto appeared instantly before Amaimon, placing a bag of the demon's favorite candies in his hand and waiting for him to get a grip on it before it fell. His arms were still healing, and he didn't need candy scattered all over the carpet should the limbs give out.

At Amaimon's still anticipatory look, hard to tell apart from his other blank expressions but Mephisto had had a few thousand years to parse those apart by now, the demon sighed and leaned down, crowding the shorter against the door and pressing a kiss to Amaimon's bruised mouth.

Amaimon eagerly returned the kiss, enjoying the way Mephisto seemed to be searching out the traces of his blood still on his tongue. And, well, a quick nip with sharp fangs to the elder's bottom lip and he hummed in pleasure as he tasted blood other than his own.

Mephisto pulled away finally, letting Amaimon pant as oxygen returned to his lungs, still not quite up to any strenuous activities just yet while his body was healing. One of those spears had gotten precariously close to said lungs and breathing was difficult.

Not that he wasn't willing to try, Amaimon licked his lips at the thought, but Mephisto was already returning to his desk to deal with his boring human duties, clearly expecting Amaimon to find his way out on his own.

Later then.

Amaimon felt a rare smile tug at his lips, bringing up his clawed thumb to chew at the long black nail in thought.

Maybe after he proved he could play nice with their little Rin, Mephisto would be in a good enough mood.

His brother was so fickle sometimes.

Rin sneezed, almost banging his head on the nearby bookshelves in Shima and Koneko's dorm where he'd been hanging out since he hadn't wanted to go home just yet. The dinner with Mephisto had rattled him and the thought of being alone in his dorm since Yukio had gone- again- was a depressing one.

"Hey, you know what they say: someone's thinkin' about you," Shima teased, popping his head up from around the corner of the shelves to Koneko's side of the small room.

Rin snorted inelegantly, thinking about the few friends he had, only two of which were girls, the third girl being Shura who was basically like an older sister and didn't even count.

"Yeah, who?"

"Well, hopefully a cute girl you can take with you to the school festival coming up," Shima grinned slyly, elbowing Rin in the side and arching his brows.

"What? Seriously? A festival?"

The excited half-demon was practically vibrating as Konekomaru pulled up the event info and showed him all the cool bands that were going to be playing at the Mephyland amusement park.

And then they got to the part where only students going as couples could get into the event and Rin felt his hopes dashed.

"So Shiemi won't be able to go with me since she's not a student," Rin groaned, tail drooping in his disappointment.

"You think Izumo?" Shima said, grin becoming mushy at the thought.

Konekomaru sighed at his friend's antics, "it's doubtful, she doesn't seem like the type to go, much less with you, Shima."

Rin snickered along with Koneko at Shima's exaggerated sounds of offense to the jab.

In the end, though, they would have to wait for classes to resume the next day to ask any of their available classmates or one of the many poor girls Shima flirted with to see if they could be convinced to be their plus one.

Rin figured at least one of them would say 'yes' and there was still a good amount of time before the deadline, so he put off rushing around to find someone like Shima was planning on to head back to his and Yukio's dorm for the night.

He knew his twin wouldn't be there. And he'd been given a perfectly verifiable reason as to why. But the fact that it was becoming a re-occurring trend in their once close relationship, that Yukio was spending more and more time out busy with seemingly anything that he could find, was disheartening, to say the least.

Rin sighed, scuffing his shoes along the pavement as he made his way towards the more secluded road to the dorm. Hanging out with Shima and Koneko had only been able to distract him from his thoughts for so long but now that he was on his own the worries returned.

That brief moment where everything had come together after the fight with the impure king in Kyoto seemed so far behind already. He had the picture they'd all taken on the top of the Kyoto Tower framed on his desk and it never failed to cheer him up. But it couldn't distract from the increasingly false smiles Yukio was wearing.

Plus, there was the weird way Shura was acting, more and more using her brash actions and drinking as a way to cover up that she was antsy about something.

Izumo and Bon were also so focused on practicing for the upcoming tests they needed to graduate that they were impossible to get out anymore. Really, if he hadn't had Shima and Koneko, and hopefully now Godaain since he'd gotten the anti-demon-seeing eyewash for him, still acting normal he would be totally alone.

And Shiemi was hanging out with Yukio. A lot. In fact, it seemed like, on the few times Yukio was home, he had to leave again to go see or had just been with her. Rin knew Shiemi had known Yukio first, and they got along so well, their personalities complimenting each other perfectly.

It still didn't feel right. He felt like the world was holding its breath. Like they were on the brink of something big and there was just a short period of normality before everything imploded.

Mood officially ruined, his tail drooped until it dragged along behind him on the ground. It was bound to get tangled and it would be a total pain- literally- to brush out later but after the day he'd had he just couldn't bring himself to care.

And then his nose picked up the scent of dried blood in the air and he looked up at his surroundings, immediately tense.

"Hmm, you're getting better at this, though your awareness is still really pathetic."

"Gah!"

The half demon twisted around like he'd been scalded, immediately recognizing the voice that had come from right behind him.

"You! You're that demon, uh," Rin grasped at his memory of the name the demon had shouted at him right before he'd tried to kill him the last time he'd gotten said name wrong, "Amazon!"

That was the wrong thing to say.

Rin found himself flat on his back, air leaving him in a whoosh as Amaimon kneed him in the stomach and pinned him to the ground with one black clawed hand around his neck and the other holding his tail to the side in a bruising grip.

"First lesson in demon etiquette," the earth king snarled, claws digging into the younger demon's skin and hand yanking his trapped tail, "my name is Amaimon and I am king of earth, seventh strongest in Gehenna under Satan."

"You will remember it this time."

Gold eyes narrowed at the panic his words and actions had created in the other. He could feel the heart beat thundering through the artery under his hand and see the pinprick pupils of Rin's eyes, totally focused on him after the glaze of shock had worn off.

But, that wasn't going to win him the wager against Mephisto so Amaimon let out a soft huff and loosened his grip on the half-demon underneath him, even being so kind as to release the exposed tail. He was nice like that.

Although he left his claws at Rin's throat as a warning not to move.

"Brother thinks you're finally good enough to talk with him," he started, tilting his head to regard Rin, "I don't see why. You don't look any stronger since we first fought."

Amaimon could see the other gulp, bracing himself before responding. Although he doubted it was with an answer to the question he'd half-rhetorically implied. He already knew nobody really understood the reasons Mephisto did anything and certainly not their youngest brother, but it would be fun to witness the attempt.

"What do you want?"

Amaimon sniffed, disappointed but prepared for such a basic question, "brother gave me a task."

Not technically the truth but the little half-demon didn't need to know that.

Rin scrunched his nose, frowning as he processed that and wriggling in discomfort until he must have realized he was still trapped under Amaimon. Not that the demon knew how it was possible to forget such a thing, but it was oddly endearing in any case, to see Rin so vulnerable.

Amaimon tilted his head, frowning, as he watched a blush take over the other's face. He was pretty sure he remembered Rin reacting a lot more violently the last times they'd interacted, which was always more entertaining for Amaimon but wouldn't really help him win Mephisto's wager.

He still didn't understand the sudden change in personality.

"Um," Rin stuttered, freezing as if to avoid touching Amaimon any further, not that it helped, trapped as he was, "can you let me up now?"

"Will you run if I do?" Amaimon asked, although from the lack of anger on the other's face he didn't think he'd have to worry about that. He wondered what had happened- and how long it had been- since he'd been in Mephisto's pocket of time being punished that had changed Rin's attitude.

His brother had a nasty habit of speeding up or slowing time down in his pocket-dimensions whenever Amaimon was stuck in them based on whatever he was being punished for at that point.

He watched Rin's eyes flicker to either side as if considering which way to run and Amaimon was about to simply resign himself to having this whole conversation sitting on the foolish demon's stomach when he nodded and stopped looking so skittish.

"Okay."

Rin felt his racing heart finally start to calm when those dangerous claws slid away from his vulnerable throat and he was allowed to get out from under Amaimon.

He rose slowly, rubbing at where rocks had been digging into his back, tail twining around his leg as if to hide from being grabbed again.

He flinched as Amaimon's slit-pupiled eyes zeroed in on the movement, impassive face still somehow giving him the feeling of being watched by a coiled snake.

But he needed to find out why the older demon was even here, released from whatever prison Mephisto had been keeping him in.

"Er, do you want to come back to my dorm so, you know, we're not in the middle of the road?"

'And so no one else sees me hanging out with one of the demon kings of Gehenna, like I don't already have enough troubles,' Rin grumbled internally, hoping Amaimon would take the bait.

At the other's assenting shrug Rin steeled his nerves, turned his back to the possibly murderous demon and lead the way.

After the meeting with Mephisto, who was apparently really the demon King of time, Samael, Rin wasn't sure about anything anymore. Nothing in his life made sense, and yet, at the same time, things were falling into place that had been up in the air since the disastrous day he'd discovered his heritage.

The thought of Amaimon being loose in the world was a terrifying one but it was also an opportunity to get answers to things he was sure the shifty and vague Mephisto knew but was hiding.

He doubted that even Amaimon knew every secret Mephisto kept, but Rin was betting the demon at least knew more than he did, and was much blunter than the principal, if also reticent with his words.

Of course, he just had to survive the encounter and whatever task Mephisto had given Amaimon.

Rin almost sighed out loud in relief when his run-down dorm came into view. With the way Amaimon had been stalking behind him like a prowling big cat on silent feet, Rin had been fighting with rising hackles and screaming instincts that said to keep the demon in sight at all times.

He walked up to the door shuffling around his pockets for the keys, for once silently happy that Yukio was out because he couldn't imagine his trigger-happy twin would be okay with a demon king in their home no matter that he'd been invited by Rin.

"I thought brother made it clear that a demon's tail should be kept hidden."

Rin yelped at the sudden question-said-as-a-statement that came from way too close over his shoulder.

At the same time he was pushing open the door, he felt his poor abused tail grabbed once again by Amaimon and given a short tug. Thankfully not as painful a tug this time, if only just, but he was getting real tired of people yanking on it like it was a leash.

"Hey! Let go!"

Amaimon ignored him, pulling the furred appendage up between them to fix an analytic look at the longer mussed strands at the end.

Rin glared, feeling his lips pull up over his fangs in a silent snarl as he prepared to fight the other off his tail.

The earth king turned a dismissive glance down at him, clearly about as impressed as Mephisto had been when he'd gotten in his face too.

Luckily it didn't come to anything. Amaimon snorted and dropped his tail, pushing past Rin to enter the building like he owned the place.

Rin frowned at the rudeness but followed, shutting the door firmly behind him and watching as the demon surveyed his surroundings with an impassive face.

Although Rin was beginning to suspect that unimpressed was Amaimon's default expression regardless of what emotion the demon was actually feeling.

"Over here," Rin said pointing to the hall that lead to one of the many empty dorm rooms, not wanting the demon to see his actual room where Kuro was probably napping or intrude on the cafeteria where Ukobach reigned.

He let them into a random room choosing the first of the larger suite style dorms he could find. Anything to not be in what amounted to a shoe box with the other like most of the dorms were.

The click of the door closing behind Amaimon made Rin shiver in apprehension. But he had come this far and knew it was too late to turn back at this point. He'd just have to suck it up and deal.

Amaimon hopped up to sit on one of the built-in window desks, one leg crossed and the other dangling to kick idly against the wooden side, pulling out a bag of hard candies from a hidden pocket in his tattered maroon coat.

The movement of the cloak and the enclosed space brought that strange scent of dried blood back to Rin and he took a deeper sniff of the air, realizing with alarm that the smell was coming from Amaimon.

And was it Rin's imagination, or were there suspiciously dark stains on the already dark material?

"Hey uh, are you okay?"

Rin cringed at his own ridiculous question. Of course, the demon was okay, he'd just shown he was perfectly capable of sneaking up and incapacitating Rin without any trouble at all.

He was proven right when all he got for his question was a curious head tilt and no response.

"I mean, last time we, er, fought you kinda' collapsed and now I smell blood on you. So, I just thought I'd ask, you know, how you were doing," Rin trailed off feeling a bright flush take over his face at his sheer embarrassment.

'Oh god, kill me now.'

"You're very strange," was all he got for his efforts.

"Hey!"

Amaimon ignored his outburst, shrugging and pulling off his coat, much to Rin's bemusement.

Rin was about to ask what the hell the other was doing, especially when it looked like the demon was about to start stripping out of his shirt too when he saw what had been making the smell, suddenly stronger without the coat to keep it contained.

"Brother was upset at me for ignoring him when he told me to stop playing with you and he was especially mad when I hit him. So I was punished until I promised not to play with you again until he says I can."

"That's punishment?" Rin almost gagged at the ragged holes that had clearly been pierced through various points of Amaimon's entire body straight to the other side. Yeah, they were healing, Amaimon's demonic powers making what would be fatal wounds on a human body into simple hindrances instead, but the appearance was nightmare inducing.

Amaimon actually smirked at him, reaching down to his stomach with one hand to trail a clawed finger around the outsides of the torn fabric of his shirt and press into the lacerated skin underneath.

Rin flinched as the demon slowly undid his tie, unbuttoned the blood-stained gold vest and pulled open the equally as stained stripped button up to reveal the several other deep wounds he had.

"You really were raised as a human," Amaimon mused, ignoring the horror of his own healing body in favor of watching Rin's reaction from beneath lowered lashes.

"What does that have to do with anything?" Rin said, still unable to take his eyes off the blood encrusted torso in front of him.

"I have no idea why brother insisted you be raised in ignorance," Amaimon repeated instead of answering, "you're lucky you have me to help you now."

"Exactly, listen," Rin said, snapping back to himself and quickly averting his eyes from the scene in front of him, "I was raised human. I didn't know demons and stuff like that even existed until this year! And everyone's expecting me to already know everything, but I don't!"

A loud crunch echoed as Amaimon bit down hard on the candy he'd been sucking on, glare over taking his features and causing Rin to shut his mouth because he'd clearly said something to piss the other off.

"You are heir to the throne of Gehenna, inheritor of father's flames and you've had your mind poisoned against your own kin by those feeble humans," came the snarl from the earth king, who'd turned his head to glare around the room as if cursing the humans and their influence in Rin's life.

"Eh, no, really, it's not that bad," Rin squeaked out, waving his hand in front of him to distract the demon's ire, "I mean it would have been great to know all this from the start, although life was definitely simpler before I knew I was a demon, but I've made some great friends now and yeah, things are definitely not good with Yukio but he'll come around, he has too!"

Okay he was rambling, Rin knew. But his monologue had definitely gotten the pissed off demon to calm down and return to watching him curiously.

Not that everything he'd babbled wasn't true. For once in his life he had real friends, something that hadn't seemed like it would ever happen to him when he'd been an outcast of a kid. Really, if there wasn't a suspended execution order over his head, his self-imposed mission to kill Satan for Shiro's death, and Yukio's weird behavior recently, he'd say life was pretty good.

Amaimon seemed to have concluded something while Rin waited with baited breath.

He flinched again as Amaimon slid off the desk and stalked into his personal space to stare down at him, bringing the scent of blood into his nose again and causing his pulse to spike in his veins.

"Never bare your fangs, your heart, or your tail to anyone, especially another demon, unless you mean to."

"What?"

Rin blinked at the seeming non sequitur, still distracted by the other's nearness and his own lack of a quick escape, backed against the wall as he was.

Amaimon sighed.

"You imply three things with revealing those," the demon continued, bringing up another candy to his mouth as he explained.

"Bared fangs will lead to a fight. It's a display of dominance and a threat rolled into one that lesser demons can't resist reacting to."

"You're lucky," he said, "I've seen you display them to Mephisto many times and brother has been more patient than I've ever seen with anyone else who's threatened him like that before."

"He's killed for that offense in the past, you know," Gold eyes glinted as Amaimon narrowed them, watching to see the effect his words were having on the younger demon.

Rin gulped, thinking back to all the times he had thoughtlessly growled, snarled or otherwise shown his teeth to the elder demon.

Granted he'd definitely felt the smarmy bastard deserved it at the time but now he was rethinking things.

"Hmm, yes, you see now. Brother really likes you, I suppose."

'He sure shows it in weird ways,' Rin thought to himself, remembering back to all the vaguely threatening overtures every conversation with Mephisto tended to carry but maybe that really was just another demon thing he had yet to understand.

"Your demon heart is equally as dangerous to display but for different reasons," Amaimon said after letting his words sink in, stepping back to examine his claws and allowing Rin to breath more freely.

"Yeah, I got that after Mephisto let you out to fight me earlier," Rin mumbled, abashed.

He'd learned that lesson. Painfully. Amaimon had almost killed him in one blow. Had the other not overtaxed his human host body when he'd revealed his own demon heart and true power Rin knew exactly how that fight would have ended.

"You," Rin hesitated, coming to a realization, eyes widening as he took in Amaimon for what felt like the first time.

"You really were just playing with me when we fought in the amusement park."

Amaimon blinked at him, bemused, "of course I was. I thought I told you that?"

Rin felt like smacking himself in the face, groaning out loud.

"Is that a demon thing? Just pick fights with people for fun?"

Amaimon frowned at that, crossing his arms as if insulted by Rin's words.

"Well, what do humans do for fun?"

'Oh boy,' Rin thought, realizing with horror that there was a truly yawning gap in Amaimon's knowledge of humans and his own infinitesimal knowledge of demons had just made itself known for what felt like the millionth time.

'We're gonna be here awhile.'

Amaimon was baffled.

He'd known it was going to take work, getting their littlest brother up to speed on his demonic heritage, but he hadn't realized just how in the dark the other was.

He wanted to go back and shake Mephisto for tricking him into doing the brunt of the work his brother was clearly too lazy to do himself.

Amaimon sucked at the remainder of the last piece of candy he'd been working on, considering the conundrum he'd been presented with.

He'd been on Assiah in a human body for at least a thousand years and yet, as he'd been told by Mephisto, he hadn't even managed the mystery of human facial expressions, let alone their actual emotions and what they meant.

Not that human expressions were worth learning, or so he'd thought. But Amaimon had a sinking suspicion that getting Rin, who was so painfully human in his upbringing, to understand his role in Gehenna he would have to do more than learn human mannerisms.

He just didn't know what that would entailed.

"Um, well, we, I mean humans, like to hang out together. Like at movies or the beach or go get food or something."

Amaimon blinked, trying to remember what the conversation topic had been for Rin to start talking about human activities.

That's boring," Amaimon grumbled, picking the conversation thread back up, "where's the competition and how do you test your strength by 'hanging out'?"

Rin scratched at his dark hair, mouth cocked down into a frown, "well, there's a bunch of fun sports to play, and we do have fighting competitions. But I guess the big difference is both sides know the other one wants to be there, and both already know the risks involved."

"Ah," Amaimon exclaimed, comprehension dawning on him, "so if I had asked you if you wanted to play beforehand you would have?"

The small grin he got in return for his question was somehow rewarding to the earth king, though he couldn't place why.

"Well, I mean, I didn't know who you were then- or what you meant by 'play'- so probably not," Rin responded, though seeing Amaimon's pout, quickly adding, "but that doesn't mean we can't now, as long as you don't try to kill me."

Amaimon looked up, eyes widening at Rin's words. Did he mean-?

"Not right now! I've still got questions and I'm kinda tired from all the crazy revelations I've been having today. But maybe later," Rin amended before Amaimon could take him up on his offer.

But if he wasn't up to that kind of play, and truthfully neither was Amaimon just yet, then he must mean-

Amaimon felt a giddy joy well up in his chest and leaned down to crush a kiss to Rin's mouth when he couldn't contain it anymore.

He pressed the younger against the wall behind him, shivering at the heat of his body. It wasn't often you got an invitation like that from another demon.

And here he didn't think the other was ever going to agree to play with him so soon! He was going to have to thank Mephisto for allowing him another chance at Rin when he saw the elder again.

The mouth beneath his was slack but Amaimon smiled into the kiss, licking slightly chapped lips and chasing the taste of fire on the other's tongue. He brought up his hand to Rin's chest, feeling the core of warmth the young demon-prince exuded and delighting in the fledgling power he knew lay beneath.

Unfortunately, that was as far as he got before he was abruptly shoved back.

"Hey! What the hell?" Rin shouted, bringing a hand up to brush his wet lips and glaring in distrust, all the good humor from earlier vanished.

"I don't understand," Amaimon responded, feeling an odd sense of hurt as he held a hand to the wound in his stomach the other had just hit.

"Wuh, you don't understand?" Rin looked flabbergasted, "you can't just go around kissing people like that!"

"But you said we could play now that you knew me," Amaimon frowned.

Rin let out a strangled noise at that, much to Amaimon's ever deepening confusion.

"Is that what you meant by play?" Rin said, voice still choked and face reddening, "I thought you meant you wanted to fight again!"

Amaimon crossed his arms, the move defensive as he tried to understand the breakdown in communication.

"I'm too injured to fight," Amaimon said slowly as he worked out what he thought had been a simple sequence of events, "you said you were tired but still wanted to play with me."

Rin was looking alarmingly red by now, "and you thought that meant you should stick your tongue down my throat?"

Amaimon chewed at his clawed thumb, habit coming to him with the unfamiliar territory he had entered, "Actually, I thought we would fuck."

Was that steam coming out of Rin? Amaimon was a bit worried to see the other appeared to be suffering some kind of breakdown in the corner of the room he'd suddenly retreated to.

The younger demon's face was clutched between his legs and he was facing the wall, tail lashing erratically behind his back.

Mephisto would skewer him again if he broke their younger brother, Amaimon determined, knowing he'd have to fix this mess if he wanted to win the wager.

And, the earth king realized, startled, he wanted to fix Rin because he had grown fond of the little half-demon now that he'd gotten the chance to talk with him.

He stepped unnoticed over to the crouched form, bending down to poke the other's shoulder and trying to ignore the incredibly distracting way Rin's tail kept sweeping just under his nose.

"Hey, what's wrong with you?"

When all he got for his efforts was a low groan Amaimon sighed and joined the other on the ground, leaning forward to rest his chin on Rin's shoulder and draping the smaller form with his body.

"This is a human thing Mephisto is always warning me about, isn't it?"

That seemed to have gotten Rin's attention, the other's tail finally slowing its movement except for a twitch of interest at the statement.

Although Amaimon was having problems focusing on what his plan had been up until that point. He was becoming increasingly fixated on nuzzling into the other's neck and chasing the scent he found in that soft black hair brushing against his cheek.

"Why are you doing this?"

Amaimon let out a huff, delighting in the way it caused Rin to shiver when it went across his neck. Maybe they could get back to the part where they had sex. Amaimon would like that very much.

That was when he noticed the rumbling growl building up in the body beneath his.

He only had a brief moment to realize the hunched shoulders were tensed when he was knocked backwards, teeth clacking against each other painfully as his jaw was slammed shut by the surprise attack.

Amaimon found himself on his back, a reverse of the way the encounter with Rin had begun that day.

He grunted as he found his breath cut off, Rin's hands clamped around his throat.

And it wasn't his imagination that things were warmer all of a sudden, flickers of blue flame appearing in patches on the furious demon straddling his body.

"Stop messing with me!"

Amaimon didn't have the oxygen to ask what he meant, heartbeat thundering louder in his ears with every passing moment he couldn't breathe.

"Nobody likes me like that!"

Wait, Amaimon blinked past the involuntary tears blurring his vision to realize Rin's eyes were also suspiciously wet. Was the other crying?

"They all like Yukio, even Shiemi. I'm just the vicious, stupid demon," Rin delivered with a choked voice, eyes clenching shut and head bowing over Amaimon, repeating, "nobody likes me like that."

'Ah.'

Amaimon finally understood and he had to wrestle with the urge to go rip that disgusting, condescending human twin to shreds for making Rin feel like he was somehow worth less because of his demonic nature.

Black spots were making it hard to see but Amaimon ignored his body's instincts telling him to attack the cause, instead reaching up and placing a gentle hand on Rin's cheek.

"Huh?"

Amaimon traced the other's jaw with his claws, brushing the few tears that had escaped away with the pad of this thumb.

Rin released Amaimon's neck, shocked out of his rage by the unexpected caress. The blue flames disappeared, leaving the other looking small and sad, haloed as he was by the dorm's pale fluorescent lighting.

Amaimon gasped out scratched breaths, chest heaving at the sudden return of air to his starved lungs. The hand he wasn't still holding to Rin's face clutched at his own throat as he tried to massage away the finger-shaped bruises that were surely there.

"Why?"

Amaimon watched with a strange fascination as his hand was gripped between both of Rin's, still held against the other's face.

"You have been made to feel ashamed of your very nature," Amaimon croaked out, coughing until he could speak again, "those simpering, weak-hearted humans have convinced you that you are evil and wrong simply for being who you are."

At the denial in Rin's face and shaking head Amaimon pressed on, needing the other to understand the conclusion he had come to, "while they hide beneath their façade of vague morals and strangled societies, you, in all your raw power and strength of heart hold up a mirror to everything they refuse to face in themselves."

"I don't-"

Rin cut himself off, starting to shiver as the emotional rollercoaster he'd just been on fully hit him.

"In Gehenna, amongst your own kind, you wouldn't be punished for your nature," Amaimon said, firmly, to make sure the other couldn't mistake his meaning this time.

"They try to contain you, keep you weak and tamable, where you should be wild and confident in your position as heir to the blue flames of our father."

"You should have hordes of demons lining up for the chance to be in your presence, let alone have the privilege of your affections."

There, Amaimon thought, he had said his piece. Let the other do what he would then.

He found that Rin was watching him with wide blue eyes, still holding his hand as if it were a lifeline. He really was going to have to find Mephisto after this and ask what the hell the elder had been thinking when he left their littlest brother to be raised in such a cruel way.

Maybe he would even punch him again. The punishment would be worth it this time.

"You- you really think so?" Rin sniffled when Amaimon just nodded in calm assent, squeezing Rin's hand in silent comfort.

And then Amaimon had the breath literally and figuratively knocked out of him again when he found himself being kissed by an enthusiastic half-demon.

Not one to look a gift horse in the mouth, Amaimon pulled Rin more on top of him, coaxing the inexperienced and sloppy kiss into something deeper and wondering if the other demon would object much if he brought his teeth and claws into play.

Amaimon didn't think he could handle it if Rin decided he wanted to stop again. He'd probably have to go find Mephisto and beg the other to take him if that happened.

He brought his hands up to card through the inky black hair, trying to map out the inside of Rin's mouth with a fervency that came out of nowhere to surprise him in its intensity.

The half-demon seemed desperate to touch every bit of Amaimon's exposed skin, sending jolts of pain-pleasure through his body every time those hands scrapped past the- finally- almost healed wounds.

Amaimon felt a purr reverberate through his chest as he got the contact he'd been craving ever since he'd been locked away for so long with nothing but Mephisto's spears impaling him.

He felt himself hardening, rubbing up against the hips above his, trying to get more of that delicious friction despite the annoying clothes in the way.

Rin gasped at the movement, breaking the kiss and arching above Amaimon, panting as if he'd just remembered he needed to breathe.

Amaimon was just about to pull him back down, and possibly tear off the other's obstructive clothing, when he was suddenly picked up by his neck and yanked back along the floor to smash into the wall behind him, a twin crash sounding from where Rin must have also been tossed.

A ferocious snarl tore out of his mouth at the bastard who'd dared interrupt him when he realized just who it was who'd interrupted.

Mephisto stood, dangerous green eyes narrowed and slit-pupil-focused on Amaimon as if daring him to keep baring his fangs at him.

Amaimon almost ignored the silent warning anyway when Mephisto began speaking.

"It seems you haven't learned from your punishment, Amaimon. I believe we agreed you would teach Rin demon etiquette, not seduce him."

Before he could come up with a way to appease his brother, Mephisto began counting.

"Eins, zwei, drei, Kuchen Kuckucksuhr!"

Amaimon had one panicked moment to search the room for Rin before he was swallowed up by his brother's damned technique and knew no more.

"Now then," Mephisto sighed, turning from where Amaimon had been, "I'm very sorry for his behavior. That was most certainly not what I had intended when I released him this morning. I assure you he will be put back in time out until he understands what he may and may not do without my say."

A crack echoed through the air and Mephisto had a strange moment when he realized it was because he'd been punched across the face.

He turned astonished eyes down to an enraged Rin, finding the half-demon wreathed in blue flames despite kurikara still sheathed by the wall.

"Let him go!"

This was… most unexpected, Mephisto thought just as all reasoning seemed to leave Rin.

The half-demon hadn't looked this out of control since his last fight with Amaimon, teeth bared in a roar and eyes appearing like the hottest part of a fire. Incandescent with rage.

"I'm not sure I understand," Mephisto said, knowing it was to an empty audience since the growling demon in front of him was hardly lucid, but he felt the surreal situation deserved it.

"Give him back to me!"

That last demand was more roared out than spoken and Mephisto had a sinking feeling of apprehension to see that Rin had given into his demonic instincts, no longer capable of conscious reasoning at all.

It must have happened when Mephisto tossed him into the wall. The surprise attack coupled with the state he'd found Rin and Amaimon in would have been enough to cause the change in the fledgling demon, still too new to his instincts to know how to counter them. It was bringing him back that would be the hardship.

Rin would have to be snapped out of it because it didn't seem like he'd be able to come back on his own until he eliminated what was causing his anger in the first place. Namely, it seemed, being with Amaimon and exterminating the intruding demon who'd come between them, Mephisto, in this case.

This was not the plan, Mephisto complained to himself inwardly, already summoning Amaimon back from his prison as it would be the quickest way to calm Rin, avoid property damage, and get some answers out of his two most troublesome brothers.

It wasn't a moment too soon that Amaimon was spat back out from the cuckoo prison, looking exactly as bewildered as Mephisto was feeling.

Rin's focus zeroed in on the earth king and the half breed made to launch himself at him as Mephisto went to stand at Amaimon's back, the implied threat halting Rin from advancing.

Amaimon immediately went lax against his chest, knowing he had a lot of explaining to do and trying to placate the elder demon.

Mephisto brought his gloved hand up to Amaimon's neck to hold him in place, keeping his stare fixed on Rin.

"What happened?"

Amaimon shifted to look up at him, although Mephisto didn't deign to meet his gaze. To take his eyes off of Rin with the way he currently was would only spur the half-breed into attacking.

He wanted his answers now and not whenever Rin would wake up after being knocked unconscious.

"He wanted to play with me," Amaimon said instead of answering.

Mephisto sneered and tightened his grip on Amaimon's neck at the deliberate obtuseness.

He had thought the temptation of winning a wager against him, however slim the odds of that were, would have kept his competitive brother in check. Especially knowing how badly the demon wanted him to come back to Gehenna. Distracting Amaimon with teaching Rin a bit more about what it meant to be a demon was just the icing on the cake.

He hadn't counted on Amaimon deciding he liked Rin after all.

"We will discuss this later," Mephisto said, the future punishment for disobeying him implied, "can you calm him enough to be rational if I let you go to him?"

"Yes, brother."

Mephisto shoved Amaimon towards Rin, admitting to himself he was in truth a little curious to see how this would all play out.

Rin immediately went from eyeing Mephisto like he'd love to tear his throat out to focusing his attention on the freed earth king.

Amaimon stumbled forward before righting himself and moving the last few feet to curl into Rin's possessive embrace.

Rin kept his arms wrapped tightly around the taller demon, pulling him back into his grasp in a mirror of the way Mephisto had held him earlier. The blue flames enveloped Amaimon but didn't burn him the way he'd been the first time he'd been introduced to them.

Clawed fingers ran down Amaimon's chest and under the part of his still open shirt as if seeking out the places Mephisto had been in contact with earlier to burn away the traces of his touch.

It was…a very nice sight, Mephisto decided, tilting his head to appreciate the way Rin tucked his nose into the crook of Amaimon's throat, still watching Mephisto with those dangerous blue eyes as if daring him to try to take the demon back from him.

He saw the moment Amaimon realized where his thoughts were heading by the way the other made the rather salacious move to bare his throat to Rin- and by proxy to Mephisto as well- angling his head back to stare at Mephisto from beneath his lashes.

"This isn't helping, Amaimon," Mephisto said, hearing the way his voice had gone rough and watching the shiver it sent through Amaimon's body, despite the way the flames licked up his skin, with interest.

"You interrupted us," the absolute tease responded. A wide smirk formed on his face just before a gasp escaped him and his eyes fluttered closed as Rin ran his fangs over his jugular.

Right, Mephisto decided, snapping his fingers and transporting the three of them to his bedroom in a cloud of pink smoke. He deserved nice things every once in a while, especially after the day he'd had, and this situation had practically gift-wrapped itself for his pleasure.

Amaimon looked like the cat who'd caught several fat canaries as he found himself pushed down to the ground and crouched over once again by Rin, who'd immediately resumed snarling at Mephisto in surprise at the sudden teleportation. Thankfully the flames were gone, but he would have to act fast before they returned and Rin burned his room down in a fit.

That wouldn't do, Mephisto grinned, vanishing only to emerge in front of the two and yank Rin up off Amaimon, tossing him on the cushy pink king-sized bed. The shocked look on the little half-demon's face was adorable but he had to set a precedence or things would end up bloody.

Mephisto gave Rin no time to adjust, appearing over him to pull his arms over his head with one hand, holding them in an iron grip and straddling his waist to keep him from kicking.

Rin looked like he was about to combust with rage until Mephisto leaned down to lock his fangs around Rin's throat and growled, the sound echoing like a tiger throughout the room.

Rin immediately went slack under him, recognizing a bigger threat when he heard one.

Amaimon chose that moment to climb onto the bed, having made the executive decision to remove the remaining tatters of his clothes. The earth king was now naked except for the slim lizard-like tail curled around his waist and Mephisto hummed at the sight, tongue laving at the throat still captured in his mouth.

Amaimon brought his hand to Rin's scalp, scraping claws delicately through his hair and bringing the trapped demon's attention back to him. Mephisto allowed it, breathing the mingling scents from Rin's throat and Amaimon's wrist before pulling back with a satisfied sigh, knowing Rin was unlikely to be a threat now.

Rin made for a very pretty sight, panting and wary beneath him, holding still in the place Mephisto had left him in as he waited to see what the dominant demon would do now that he'd made their positions clear.

He turned to gaze down at Amaimon from where he sat over Rin, gesturing with a nod to both of their still clothed bodies, "well? You've been begging for this all day, it seems. Get to it."

Amaimon complied, reaching forward to carefully unbutton the suit Mephisto had chosen to wear that day. Mephisto watched with dark eyes as the other slowly peeled off the layers of his clothes until all that remained were his gloves and his slacks.

Without warning Mephisto dragged Amaimon to him, bringing his forehead down so that his hair framed the other's face and making sure he was looking into his eyes.

"I am going to let Rin take you and then I will take you," he breathed into the mouth under his, "do you understand?"

He swallowed the involuntary moan that came out of Amaimon in a kiss that was all teeth and heat, crushing their bodies together over the still prone Rin.

Without looking he snapped his fingers and Rin's clothes and his own vanished to reappear folded neatly in a nearby chair. The half-demon beneath him hissed at the sudden exposure of his skin to the air, bringing his hands to Mephisto's waist as if to push him off. Mephisto put a stop to that by grinding down onto the bare skin revealed to him now and Rin arched back into the bed, eyes glazing over at the sensation.

He allowed himself a moment to revel in the feeling, dragging his hips over Rin's once more in a deliberate movement that sent electricity singing through his nerves before he forced himself off and to the side.

"Prepare him and yourself, Amaimon," Mephisto instructed roughly, realizing his fangs had lengthened and knowing that meant his eyes and ears had taken on their true demonic appearance as well.

Amaimon didn't need to be told twice, moving over to Rin's waist and leaning down to lick a long, slow strip up the demon's inner thigh.

Rin panted helplessly, hair sticking to his forehead and flushed face as his eyes tracked the earth king's path.

Then the half-demon let out a groan as he was enveloped by Amaimon's warm mouth, thrusting up into the inviting heat.

It was a good thing Amaimon had no gag-reflex to speak of as Rin, out of his mind as he was, brought his hand to the head over him and pushed into it at a merciless pace.

Mephisto felt a heated growl reverberate through his chest. He knew Amaimon more than had the strength to hold Rin down and go at whatever speed he wanted to. The shameless demon was letting himself be used in such a forceful way.

However, if he let them continue the fun would be finished far too soon so he reached over and dragged a clawed finger down Amaimon's spine to end at the base of his tail, tapping it pointedly to remind the demon of his other task.

Mephisto felt his breath catch and he inhaled sharply as, instead of pulling back from Rin like he'd expected, the earth king slid his tail from the tight loops around his waist that he'd kept it wound in.

The slim green tail waved in lazy, careless coils behind Amaimon, the demon knowing the sight would entrance Mephisto. Indeed, he almost moved to grab it as it made a pass near his hand but he managed to restrain himself, knowing his patience would pay off tenfold in the end.

He was rewarded to the sight of that tail skimming up Amaimon's leg before it reached his rim and began to tease at it, causing the demon to arch his hips back up into the blunt tip.

Amaimon moaned around Rin as he impaled himself on his own tail, pushing back onto it at the same time as Rin pushed his head down.

Mephisto knew the masochistic demon wouldn't wait very long to get to the next step and was proven correct when Amaimon only thrust in a few times before finally disengaging from Rin and sitting up, much to the other demon's wordless frustration.

Amaimon looked down at Rin, eyes heavy with lust and mouth slick with saliva, bruised at the rough treatment he'd been at the mercy of.

He looked over at Mephisto and his lips slowly lifted in a sly smile.

Before Mephisto could think of what that look could mean the demon lifted himself over Rin and sat down without warning, both of them shouting at the abrupt feeling.

Amaimon's tail was still in him, right alongside Rin now.

Mephisto hissed out a long breath at the sight, heart thudding in his chest and hands clenching in the sheets until they almost tore and he came back to himself, realizing what Amaimon meant for him to do.

Well.

Well, that was a far better plan than he'd had, and he wasn't too proud to admit it, either.

Amaimon was bowed over Rin, elbows bent until his hair tickled at the chest beneath him when Mephisto finally took pity on him and shifted until he could kneel behind the two.

He dropped his head over Amaimon's spine, placing a kiss onto one of his vertebrae. He lined himself up, breath held as he watched as Amaimon slowly slid his tail out of his stretched entrance to let it trail along Mephisto's heated skin in a rasp of smooth scales.

That was all the waiting Mephisto could take. He pushed into that tight heat, hearing the twin groans of the two demons beneath him at the added sensation, so much larger than the tail had been.

He didn't give them time to adjust, fucking up into Amaimon alongside Rin, the intensity almost too much to take at once.

For his part, Rin had given up, mind gone to the pleasure he'd never experienced before, hands scrabbling at the bed beneath him and head tossed back in a silent scream.

Amaimon couldn't do much of anything at all except take the punishing thrusts, body shuddering at the force.

Mephisto hooked an arm around Amaimon's waist, adjusting the angle to go deeper and pull the other demon down at the same time.

Amaimon cried out as Mephisto hit that sensitive bundle of nerves inside him, tightening as much as his body could, being filled as it was.

That was when Rin finally gave out, coming in a hot rush that filled Amaimon's insides with a warmth that almost had Mephisto following suit had he not had thousands of years of practice in extending the experience as long as he could.

Mephisto didn't hesitate long in pulling Amaimon off the younger demon and throwing him onto his stomach to the side, slamming back into the raised hips as the earth king shouted at the rough handling.

He pressed Amaimon's face further into the mattress, delighting in the expanse of the demon's exposed back. He raked his claws down across shoulder blades to leave red trails that he dragged his tongue across making Amaimon howl at the pain mixed with pleasure.

Mephisto could feel himself getting close and decided to up the ante, unwinding his own tail from around his waist and twining it with Amaimon's, gasping at the sparks that danced across his senses as he did.

His mind went hazy as he slid the two lengths against each other, the pleasure from two sources at once overwhelming until it was the only thing he was aware of at all.

He brought both their joined tails up to his mouth and bit down, whiting out and coming with a muffled shout into Amaimon, who didn't last any longer after Mephisto brought the tails into play.

He came back to his senses slowly, luxuriating in the afterglow and feeling a rumbling purr coming from his chest as he relaxed down onto the bed on his side.

Amaimon pulled away and slumped to the other side, panting as he, too, came down from the exertion.

Mephisto scratched his claws lightly along the demon's flank, enjoying the way Amaimon's breath shivered through him, slowing down in increments as he relaxed into the covers.

He leant over to grab Amaimon's hair and place a rough, open-mouthed kiss on the other's lips, ignoring the tired grumble he received in return until the earth king gave in and allowed him to have his way.

That was when a strange squeak sounded from where they'd left Rin.

Mephisto slowly broke the kiss but kept his head where it was to look up at Rin with a smirk, murmuring, "I believe he's come back to his senses, Amaimon."

Amaimon grunted an acknowledgment and wiggled further into the covers, draping his tail over his jutting hip.

"Does that mean I have to go back to explaining things now?"

Mephisto scowled down at him, sniffing at the disrespectful tone, "I should make you for so poorly following my orders. But I believe this time I'll let your punishment slide."

"Did we- did we just, uh," Rin couldn't complete his question, going back to the bashful youth he was instead of the dominant demon his instincts had turned him into. A beautiful sign of things to come, Mephisto was sure.

"Fuck."

"Have sex."

Rin squeaked again at their blunt words, pulling one of the many pillows he'd been laying on against his face as if to suffocate himself to escape the embarrassment he was feeling.

"What is wrong with him?" Amaimon groused, dropping onto his back and tilting his head to the side to consider the younger demon.

"I believe he's suffering from the human condition. A tragedy but nothing we can fix right now, unfortunately," Mephisto snickered.

Rin grave a strangled yowl at the teasing words and chucked his pillow at the two lounging demons, "don't laugh at me, bastards! This is your fault!"

Mephisto sighed good naturedly, running a hand through his sweat-drenched hair and tugging at the knots he found. He'd have to take a shower later.

"I thought you were supposed to be teaching me how to be a demon, not- not that!"

Rin crossed his arms across his chest, hiding his lower half under the blankets. His tail was still waving behind him in his irritation.

Mephisto looked down at Amaimon, seeing that the other was sharing the same thought he was.

"Didn't I tell you there were three things a demon must learn to hide?" Amaimon said, face as innocent as it had ever looked, which was to say, not at all, "we covered your fangs and your heart, but I never did tell you about your tail, did I?"

"Wuh?"

Rin didn't get a chance to puzzle that one out before he was pounced on and tackled back into the sheets.

"Hey! Ah-!"

Rin's voice trailed off in a shocked moan as Amaimon and Mephisto showed him a totally new way to toy with his tail, forgetting what he was supposed to be protesting as he was pulled into a new round of play with the two insatiable demons.

He didn't get a lot of chances to complain about his demonic heritage after that.

And Fin!

So what you've just witnessed is my first attempt at writing smut. Getting over that first hurdle of using the word "fuck" as anything but a swear was pretty funny, let me tell you.

I gotta say this was a wild ride and I churned this bad boy out in two-ish days of inspired writing, which after the year of writer's block was a breath of fresh air. So let's hope I can maintain the enthusiasm and finally update my other poor fics lol

Thanks for reading, and let me know what you guys think!