Rin had been waiting for this day for pretty much the entirety of her teenage life.

The circumstances would never be more perfect. Yukio was out of town for two whole days on a mission, and Shura left to go home and/or presumably get passed out drunk at promptly 9pm most weekdays, leaving her completely unsupervised from 9pm to whenever Shura decided to drag herself out of bed the next day. Usually around noon. This meant the entire basically abandoned dorm building which was usually occupied by herself and her brother was now left entirely to her, for her to use however she pleased, and no one could stop her, least of all her own nearly non-existent sense of self-preservation.

Rin Okumura was gonna throw a bangin' party.

With a hearty amount of persistence on her part, she managed to convince everyone that this was a fantastic idea. Well, maybe not quite fantastic, but the point was that everyone was coming. They had had a rough time recently, after all! First with the whole Impure King deal over in Kyoto, and then with that squid monster. The latter had been more remarkable than it should have been since it had resulted in Rin wearing a swimsuit. She hadn't thought twice about it until Shima took it as an invitation to be even touchier than normal, which consequently resulted in Yukio shooting a bullet through one of said touchy hands. He claimed his finger slipped, but all the boys gave her a wide berth for the rest of the mission nonetheless.

Anyhow, the point was they all deserved to relax and let loose a little. Which is why, in exchange for a small mountain of gourmet treats and a promise of more to come in the following weeks, Kuro had given her access to a small portion of his stash of silver vine sake.

Giggling to herself at her own brilliance, she riffled to the bottom of her underwear drawer and pulled out the rather large container of sake and then, even more dangerous than that, a pair of shorts. Short shorts, to be precise.

Now, it wasn't like she wanted to wander around dressed like the old bag all the time or anything, despite what Yukio seemed to think she was far from promiscuous. But sometimes she wanted to wear clothes that didn't fall in line with a Catholic girl's school dress code, like shorts more than three inches above the knee, or a shirt that exposed- gasp- her upper collarbones. Besides, she was a young girl! So what if she did want boys to think she looked cute? It wasn't like she couldn't beat them off if she wasn't interested.

And so it came to be that at 10pm that night the cafeteria of her dorm was filled with all of those she had come to call friend over the past year or so of cram school, laughing, passing the sake, having a good time. She wore her short-shorts with no brother around to chastise her for them, and maybe she noticed Bon looking at her legs, and maybe she liked it. Maybe the booze was going a little to her head, and maybe she decided to actually flirt with him a bit while she had the chance. So what? Tonight, no one could stop her. Tonight, she had everything under control and accounted for, and she could do whatever she wanted.

Everything accounted for.

Except, well, there was just one little thing she may have forgotten about.

Ukobach may have been her friend after the Great Kitchen Battle of 2011, but at the end of the day he wasn't her familiar. Oh no.

He was Mephisto's.

It wasn't that Mephisto had no trust in his littlest, human brother to look after their only sister. No, it was just that he had very little trust.

So, enter Ukobach, who was under strict orders to report immediately back to Mephisto should Yukio fail in any such brotherly duties. Especially relating to boys.

As such, when Ukobach turned up in Mephisto's office and interrupted his 47th marathon rewatch of Lucky Star, he knew things had to be serious.

"A party you say!?" The demon exclaimed. "Rin in booty shorts you say!? Flirting with a BOY you say!?"

That was all the information he needed. It was a real shame, he had never wanted to have to personally murder one of his own students, but desperate times call for desperate measures. Horrible measures. Violent measures.

He jammed the port key to his sibling's dorm into the door of his office with a little more force than necessary, and ripped the it open as he turned the knob, amazed that he didn't break it off the hinges. What he saw when he opened that door made him freeze. This was his worst nightmare. No, worse than his worst nightmare. Worse than the nightmare worse than his worst nightmare!

The scene before him was one typical of human teen debauchery. Teens in casual clothing were spread around the room, faces flushed with varying stages of intoxication. This isn't what disturbed him, oh no, at this point he WISHED Rin had been passed out drunk like the Shima boy, what she was actually doing was much, MUCH worse.

His little sister, his only sister, his pure, adorable, untainted imoto, was dressed in the heinous invention known as short shorts, tail exposed to the world, and then, even worse than that, she sat straddling the "Bon" boy's lap, arms wrapped loosely behind his head, with their lips locked in that filthy human custom known as a kiss.

Well. He knew this day would come sooner or later. It was time to execute Rin Protection Plan Operation J.

He knew he should have made True Cross a girl's only school the second Rin was accepted/forcibly enrolled by yours truly. It would have been a hard sell, but he could have swung it with the Vatican if he came at it from the right angle. Now look what's happened. A boy's about to be dead.

"Um, Rin, Bon? I think you might wanna cut that out now..." Konekomaru, the only one of the group that appeared to be sober, tugged at the sleeve of his sister's shirt.

"Huh?" She pulled away to turn her head to the boy and he finally got a good look at his sister's face, flushed a deep scarlet with intoxication. "Wha the hell are ya talkin' 'bout?" She slurred.

The boy merely pointed in the direction of the doorway where Mephisto stood, still frozen in horror.

"HUH?" She exclaimed, making no effort to move from her current position. "The hell are you doing here, clown!?"

Bon, for his part, went from being cast pink with a mixture of alcohol and embarrassment to being white as a sheet with impressive speed. "Get off, Rin!" He demanded in a desperate last bid for his safety.

"Why the hell would I do that, huh?" She leaned in closer and shot the headmaster a suitably devilish look out the corner of her eye. "I'm comfy here."

"So you and Rin are on a first-name basis, then, Suguro Ryuji?" Mephisto asked in a tone that made Bon feel like it might be for the best if he went ahead and slit his own throat to save the other the trouble. Would probably be a lot less painful, too.

"Well-"

"What of it!? Clown." Rin demanded, still not removing herself from the boy's lap. Which, to be honest, might have been the only thing keeping him alive at this point.

In a rare show of anger, Mephisto crushed the door-knob in his hand flat. "Rin. Remove yourself from the human."

"Why doncha MAKE me?" She mocked, sticking her tongue out at him childishly.

"Fine. If you want to play that way, then I will."

"Huh?" She blinked, and the next thing she knew she was in... some kind of... void?

"Oh my!" She heard a familiar voice call from over her shoulder.

"Oh no."

"What are you doing here, imoto?"

"Why the fuck are you here, Amai-whatever!?"

"Hm." The green-haired boy placed a finger on his chin in thought. "Well that's not very nice." He floated closer, taking a good look at her face, wrinkling his nose as he caught a whiff of her breath. "Ah, I see! You're drunk!"

"What of it, Amai-ma-min- whatever the hell your name is."

"It's Amaimon, but I already told you, you can call me nii-san!" He informed her in a tone that resembled cheer. "I wonder what you did to make older brother throw you in here. It must have been pretty bad~"

"I don't know what the hell you're talkin' 'bout," she insisted. "All I did was throw a party and make out with Bon and the clown lost 'is damn mind."

The grin on Amaimon's face dropped so suddenly that if it had been tangible, and they hadn't been floating in an endless void, it would have shook the floor with a resounding thud. "Sorry, imoto, I must have heard you wrong, because it sounded like you said you kissed the rooster boy."

"Rooster boy?" She asked, exploding into laughter. "Ah, that's fuckin' funny, Amiamomo, I'll give ya that one."

"This is no funny matter, imoto!" the demon king protested. "Tell me I misheard you!"

"Hm? But you didn't. What, are you gonna get mad about it too?"

Amaimon didn't acknowledge her, instead turning towards the depths of the void. "Aniki!" He shouted pointlessly. "Let me out! It's not fair if you get to kill her suitor all by yourself! I'm her older brother too! Aniki!"

Not sure what most of that spiel was about, but very on board with the 'let me out' part, Rin joined in on the shouting. "Yeah, Clown!" She cheered. "Lemme out!"

"ANIKI!"

Meanwhile, outside the void, the esquires were fairing little better than their trapped classmate. One second Rin was there, lounging on Bon's lap like queen of the castle, and then she wasn't, leaving only a fuming Mephisto behind, holding Bon up effortlessly by the collar.

"Since I am a kind and benevolent headmaster, Ryuji Suguro, I will give you 10 seconds to tell me why I should not kill you where you stand."

"She kissed me first, I swear!"

"Like I would ever believe that! My darling imo- I mean charge, would never do something so vulgar."

"No, headmaster, he's telling the truth!" Konekomaru shouted in defense of his friend.

Izumo watched the situation unfolding before her with a sigh. Everybody who was anybody knew that Mephisto Pheles was a demon king, aka one of Rin's many older brothers. One of the more powerful ones, too. You'd think someone as old and powerful as Samael would be above pettiness like bullying human boys for fraternizing with his little sister, but apparently wisdom and age really didn't correlate after all.

"Headmaster." She said dispassionately, wondering in the back of her mind why she continues to stick her head out for these losers. At least this time she could blame the booze. The demon's eyes shot over to her, but his grip on the boy's collar didn't waver. "He's telling the truth. Rin really did kiss him first. I'm sure Bon has no ill intent towards her, sir."

"And what do you know of his intent?" Mephisto borderline hissed. Wow. Izumo barely restrained a severe eyeroll. This was ridiculous.

"He is an aspiring monk, sir. He's very focused on his duties, and not much else. He's so one-track mind about his whole 'killing Satan' thing, it's honestly irritating. I doubt he even notices that Rin's a girl at all."

"Are you calling my imo- my CHARGE, boyish!?'

Izumo couldn't believe the stupidity she was witnessing tonight. "No sir, that's all Bon's tunnel vision, nothing to do with Rin at all."

"Hmm." Mephisto squinted aggressively Bon's face, searching for any spec of guilt. Unfortunately, the only prevalent emotion on the boy's face was terror. He knew what the Kamiki girl was trying to do, he was a demon king, after all. If Shura's flirtiness couldn't pull one over on him, this inebriated 15 year old certainly couldn't. Still, he really did prefer not to kill his own students if he could suitably inspire distance with a fear of death just as well. And this boy did keep his sister alive in Kyoto, not that he would have ever let her actually get hurt of course. Mephisto, in his infinite generosity, decided this, combined with the slight uncertainty of the whole situation, was just enough to let the boy live... for now.

Mostly because he didn't want to deal with his sister's outrage if he actually killed a human, really.

"Alright." He placed the boy on the floor and released his shirt, which now tented oddly around the collar from his grip. "Consider this your one and only warning, Ryuji Suguro." He flashed a grin that he knew emphasized his inhuman canines. "Get a second strike and you're out, hm?"

"Y-yes, headmaster," he agreed reluctantly, but looking suitably shaken for now.

"Very well. You all go back to your respective dormitories now, I'll deal out your respective punishments in the morning." He watched as the grumbling student body stumbled out of the room, all desperate to be the first to leave, the Shima boy's still unconscious body thrown over Bon's shoulder like a sack of potatoes.

With a sigh, he summoned the cuckoo clock that contained his infinite prison and opened the door to outraged screams of "Aniki!" and "Clown!", respectively. What he wouldn't give for his little sister to call him "Nii-san" like his beloved moe characters instead of her rude nicknames, be he supposed that required her actually figuring out that they were related, which he doubted would happen until someone told her directly.

He sighed again, freezing the both of them so that Amaimon didn't rush out and do something brash, dragging his sister out by the nape of her shirt like the mother of a disobedient puppy. Which was not entirely unlike how he was feeling at the moment.

"Tomorrow, imoto," he said, dropping her into her unmade bed in the room beside her brother's, "you and I are going to have a long conversation."

He gave her one uncharacteristic knock to the head to make sure she stayed konked out, as he really couldn't deal with her right now, especially drunk off her ass like she was at the moment. He thought about just leaving her like that, she was half-demon after all, it wasn't like she was going to catch a cold. He sighed. How lucky that he had had only brothers to this point, if sisters made him this soft. His father should learn to keep it in his damn pants if this was a possibility. He really couldn't handle more than this.

Knowing that if anyone saw him he would never be able to hold his head with pride again, he gently pulled the blankets over his sleeping (ie knocked the fuck out) sister, and then, deciding that wasn't good enough, tucked them in for good measure.

"Sleep well, little sister," he said, making his way to the door, "Your other brothers and I are about to have a long strategy meeting, and you aren't going to be happy about its results. Someday you'll thank us."

Probably.

The following day Rin got the feeling that perhaps her party hadn't been the best idea after all. She wasn't sure why at first, her memories lost somewhere in the smoky haze of her hangover, but for some reason her stomach was knotted in a whole lot of dread and she didn't appreciate it.

She got ready and went about her day as usual, blissfully unaware of the events of the previous night until she was walking down the hallway and made eye-contact with Bon in passing. Bon. For some reason, she felt like something significant had happened with Bon. With a gasp, it all came rushing back to her, from when she had kissed him (which he kissed back, she would like to point out), all the way up to being thrown into some void where Amaimon also was for some reason.

Both parties froze. "Bon." She stated simply.

"Rin."

Uh-oh.

Yukio was going to kill her.

That is, if he didn't kill Bon first.

AN: Poor Bon. He didn't know what he was getting himself into.