AN: First Blue Exorcist Fanfic so be gentle. Does not own the series but please enjoy!

Chapter 1: What Could Possibly be the Worst Day EVER!

Mephisto tried to remain calm and composed as he tried to asses a rather… dire situation presented before him in his office. But this…

"Pffft… hahaha…"

…is just…

"PPPPFFF-HAHAHAHAHAHAHHAHAHA!"

..too funny!

Mephisto's head lay on his desk, banging his fist on it as he cried with laughter.

"Oh sweet mother of Gehena! Of all my long years of living, this is by far the best I've ever seen! I really have such troublesome brothers!"

Because really, he turns his back for five minutes and then this happens. Of course he knew these two were gonna fight if they ever crossed paths again, but never did he anticipate the end result.

"Oh wait! I think the word 'bothers' is no longer the appropriate term given the situation we are now in, don't you agree?~"

"SHUT UP YOU STUPID CLOWN!" came the voice of Rin… though his voice is slightly more feminine than usual. That, as well as other obvious physical changes, caused the boy to blush in embarrassment and in rage. His emotions also caused his demonic flames to erupt wildly around him, the heated glare he gave to Mephisto promised murder.

But the demon continued to laugh.

"Now now, is that any way to speak to your elder brother? Especially when he may have a solution that could get you two out of this-pfftheeheehee… mess."

The half-demon huffed and the flames slowly disintegrated.

"Brother…"

Mephisto left Rin's gaze and faced the other victim in question. Amaimon, as usual, appeared impassive, but the constant shifting of his shoulders revealed that something's bothering him.

He grinned. "Yes Amaimon, what seems to be the problem?"

"My chest hurts."

He had to keep himself from laughing again, knowing very well the reason for his brother's discomfort. The two were still in their regular clothes but now it's going to be difficult for their new 'assets' to accommodate them.

"Unbutton your vest and part of your shirt. That should relieve the pressure."

Amaimon simply nodded and proceeded to do so. Meanwhile, Mephisto could see Rin trying really hard not to look. He couldn't blame him. Amaimon's chest could rival Shura's at best. It's no wonder the Earth King's clothes were suffocating him. The thought of taking the two out shopping suddenly came through his head and he found himself feeling giddy at the thought. Oh the humiliation, the hilarity!

The door to his office slammed open to reveal a frantic Yukio. Just in time!~

"Sir Pheles! I came as soon I heard Nii-san was in trou-"

…

…

…

Rin pointedly turned his back away from his younger brother, probably hoping he'd mistake him for some random girl wearing male clothes that are much too big for her, and making himself as small and unnoticeable as possible in his chair. Sadly…

"Hey little bro, your twin is here…"

"Shut-up!" Rin gritted his teeth at Amaimon, face flushed. The greenhead tilted his head.

"Why are you so upset?"

The half demon growled and was about to grab his sword when a towering figure loomed over him. Rin tensely looked up to see Yukio looking down at him, eyeglasses illuminated giving off that mysterious calculated look. This person is clearly wearing his brother's clothes. But this person is a she, with face like his brother's if he were to be female, with that messy midnight blue hair that reaches her lower back.

And those sapphire eyes…

The pointed ears…

That demon tail…

Sweat appeared on his skin and his limbs visibly shook.

"N-Nii-san… is that you?"

Rin gulped and gave an awkward toothy grin.

"Hi Yukio." He inwardly winced at the girly squeak, now feeling more embarrassed than ever.

Yukio stared for a good long minute until he turned his head like some mechanical robot toward Mephisto. Eyes hidden behind the light of his glasses and his is expression deadpan.

"What happened?"

Mephisto, for the life of him, could not wipe the grin still present on his face even if he wanted to. His mind is filled with different possibilities that may transpire due to this wonderful incident. He cleared his throat, getting back to the business at hand.

"Ah Yukio, so glad you can join us! Your guess is as good as mine on this one. So Rin, Amaimon, how about you two shed some light as to what exactly happened, hm? It'll help us greatly in finding a way to change you back.~"

Well, Mephisto didn't really need a full explanation. He could pretty much guess what had happened just by looking at the state of his office, where their fight took place. Thankfully, not much was severely damaged and can be easily fixed or replaced… except for the contents of his bookshelf. Other than old books and splintered wood, there laid a uniquely carved wooden box. In the box were vials filled with elixirs he had mixed together himself. They now lay on the floor, a heap of broken glass and liquid mixed together. Some of it he could see on the clothes of his younger brothers.

Amaimon focused his attention on biting his long nail. Watching him, Mephisto made a mental note to fix his hair. The reason why is because it's basically a wild mess of green curls. Though his hair only reached his shoulders, he could tell that going through those locks would be a nightmare. It would be like trying to tame a lion fresh out of the wild. A very mean, very hungry lion. Anyway, it appears that the Earth King isn't going to explain anything to them, so all attention was focused on Rin.

"Um…" the boy shifted in his seat, not liking the eyes on him. Also, Rin had a feeling the damn chairman knew the cause of this change and just sought to humiliate him further. I doesn't help that Amaimon is doing practically nothing and isn't freaking out about being turned into a girl like he was. In huffed and crossed his arms, inwardly shuddering when the action caused his boobs to squish against his chest. Don't get him wrong, he likes boobs, just not when they've suddenly grown on him! He tried to ignore them.

"Well long story short, I just wanted to see Mephisto for something, but instead I find him in his office." He pointed to the Earth King, still biting his nail rather intently as he ignored his younger brother. "We spat a few words, fought, hit a bookshelf, and some goop fell on us." He bared his demon fangs at Mephisto. "Next thing I know, I become a chick! Just what the hell was that stuff?!"

Mephisto giggled like a school girl receiving glares form the Okumura twins. "Well Rin, that 'goop' happens to be potions I created for…special purposes."

The half-demon gave a horrid look. "You mean you sometimes like to change sexes?" Just when he though his demon principle couldn't get any creepier.

Mephisto laughed. "No no my silly little brother. What I had in that box were different potions containing different abilities. If you knew anything about alchemy, you'd know that mixing potions together can result into creating an entirely new potion! However, instances like this are rare depending on what kinds potions are mixed. It's actually a rather dangerous experiment that usually leads to catastrophic results. In your case, consider yourselves lucky, because demon or no there's a high possibility you could have died."

Rin paled and Amaimon stopped biting his nail, staring fully at his older brother.

Yukio coughed and adjusted his glasses. "I'd have to agree with him Nii-san. Mixing potions have never been practiced carelessly for that reason. Still is there a way to remedy this?"

"Of course there is!" Mephisto stated happily. "The effects are not permanent. Though, it will take some time before you turn back to normal. These are strong, highly advanced elixirs that last longer than standard ones, but how long exactly will depend on how much got spilled on you, which none of us know. So you two will just have to adjust being females untill something happens."

Amaimon continued to stare blankly at him but bit his nail quite aggressively, drawing a bit of blood from his finger. Clearly he wasn't pleased by the news given to him.

"You cannot be serious!" Rin voiced his displeasure. "I can't parade around school looking like this!"

"I'm afraid you don't have much of a choice," he shrugged. "The best and safest way to go about this is to just simply wait it out."

Rin groaned and slumped in his seat, arms crossed again. Yukio patted his shoulder. "It's okay Nii-san. Like he said, you could've ended up in a worse situation."

The half-demon blew away the long locks from his face. "I guess you have a point there…" Then his eyes lit up. "Hey, does this mean I don't have to attend school because of this? I mean, it'd be weird if I have to explain to my teachers and classmates why I've suddenly turned into a girl, right?" Rin may not like experiencing the life of the opposite gender, but if it meant getting a break from his classes, then maybe it won't be so bad.

At this, Mephisto had this sadistic grin that could probably shatter a person's hopes and dreams, like Rin's when he said, "Nope. You're still going to attend school."

The incredulous look was priceless as well as the feminine shriek when he yelled out "WHAT?!"

"I'm sorry, but what just transpired here cannot go unpunished. Not only did you trash my office, but the ingredients I used to make those elixirs took a good chunk of my lifetime to collect, and I hate to have such valuable effort go to waste." Though he was still grinning the demonic change in his eyes proved he was deeply seriousness, and the twins, even Amaimon, stiffened at the intense gaze.

"So what's going to happen is you'll still attend school, but as a transfer student with a new name!~" and just as quickly the principle reverted back to his flamboyant cheery self. "Hmm let's see… Hotaru has a nice ring to it. Yes! You Rin, will now be addressed as Hotaru-chan!"

"Firefly?" Yukio muttered at the name picked.

"Hey! Who said you can pick names for me?! And how the hell is all that going to work?!"

"Oh I have my ways my dear Hotaru-chan.~~ I am the head of Blue Cross Academy after all," Mephisto sang, enjoying the way he got his little 'sister' riled up at the sound of her new name.

Rin, now Hotaru, growled and pointed to Amaimon, who was oddly quiet during the whole conversation and was currently sucking on a lollipop he had tucked away in his coat. "And what about him? He's the one who tackled me into the bookshelf, so he's just as at fault as I am!"

"He's not off the hook I can assure you, but what I do with him is my business. In the meantime, you two should get back to your dorm. We'll discuss this matter further tomorrow," He dismissively waved his hand, signaling the twins to go.

Rin was about to say something else but was stopped by Yukio's hand grasping his arm.

"Let's go Nii-san. We need to clean up your injuries," he said firmly, leaving no room for protest. Reluctant, the older twin complied and was led out of the office; the door closed with an audible click leaving behind the two demon kings.

Amaimon felt Mephisto's eyes bore onto him like a laser attempting to slowly melt his head until he was nothing but bone. He knew his brother wouldn't do anything but stare until he acknowledged him fully. The Earth King's gaze left the lollipop he was sucking on and lifted his head to face his brother, only to see the fury in the Time King's eyes return again.

"Obey simple rules is all I asked from you Amaimon," he said calmly, hands folded together on his desk, still eyeing him like a hawk. "And yet you can't even do that right. Tell me, since when did I allow you to attack Rin today?"

"Never big bother," Amaimon replied, face leaving no emotion, but inside he was carefully choosing his words that'll not anger his brother further. "I only attacked him because he provoked me, and I got mad."

Mephisto scoffed. "An unworthy excuse little brother, as usual. I don't think I need to remind you again the consequences should Rin ever be killed by your hands. I am known for my patience as a demon but even I have my limits. And it's getting thinner every time you disobey me. Let it be the last time we ever need to discuss this."

Amaimon nodded obediently, not saying anymore knowing it'll only make things worse for him. His intentions for being in his brother's office were simply to meet said bother in hopes to relieve his boredom. When discovering he wasn't there, he decided to search for Mephisto's hidden stash of candy. The moment he saw Rin enter, his immediate instinct was to finish where they left off at the camping trip, not wanting to accept that he got beaten by a mere half demon even if he is the son of Satan. However, Mephisto's warnings quelled his demonic urges to do any of the sort. Despite that, Rin still saw him as a threat and brandished his sword, Kurikara, expecting another round with the Earth King.

_ …. …. …. _

Several minutes ago…

"What the hell are you doing here?!"

"Hmm… I could ask you the same thing little brother."

"I am NOT your brother! As if I would ever want to be related to someone like you, now get lost!"

"I got here first. You leave."

"Grr… just why are you here? Are you here to take Shiemi again?"

Amaimon said nothing and just stared blankly for a moment. "Who's that?"

That actually caused the boy's blood to boil and his flames to dance wildly with rage. The heat of the bright blue fire scorched anything that happened to be near it.

"How…" he seethed. "How could you not know? She the one you planted a parasite into her brain before you kidnapped her!"

Amaimon's eyes lit up and clapped his hands together rather childishly, now remembering who he's referring to.

"Oooh, you mean that girl who I made my wife right?"

Satan's flames intensified, matching Rin's hatred.

"She's not your wife!" he roared, charging at him, aiming so slice him cleanly in the midsection, but Amaimon effortlessly dodged the attack.

"I know. I just used her to get to you, so you could use your powers to fight me for real. It worked." The greenhead studied the flames with interest. "You needed to stop hiding yourself little brother. I don't see why you desire to be like those humans so badly. There's nothing good about them."

"That's because I am human and I'll never allow you to use my friends like that again!" Rin swung his sword again but missed. "Everything is just a game to you and I hate it! Not once do you ever consider how the other person might feel and just do whatever you want because you're superior to them! Why the fuck does all of that matter anyway? You're strong, so what? There's more to life than that and you're just too stupid to even see it!"

Rin barely blinked before a fist hit his face, reeling him backwards. Not a second after he could process what happened Amaimon had him by the neck and slammed him to the bookshelf, cracking the polished wood and letting some of the books fall to the floor. At the very top lay a carved wooden box. The impact caused it to slide to the edge a bit.

"I'm not stupid," the Earth King said evenly but carried a dark message as he griped tighter, making Rin choke and lost hold on his demon sword. "If you knew how things work in Gehena, you wouldn't be saying that. Of course a half-breed who lives among human weaklings would become just like them. You make me sick. Don't talk as if you know me."

Seeing the boy struggle under his hold as he desperately tried to take in air sent pleasing shivers down his spine. He could easily snap his neck like this, or he could just let him slowly suffocate to death. Rin clawed at his hand for release but to no avail, feeling his strength slip fast and his eyes losing focus.

"Power and dominance is everything. It's how we are raised as Demon Kings. It's how we survive in the world of Gehena. Possess neither of those things and your worse than dead. In your case you won't last a day." Amaimon grinned sadistically at the boy's heated face and glazed eyes. "You don't deserve to be Satan's son. Faint-hearted demons never last long anyway. So die."

Before he could squeeze out the last of the air out of the half-demon's lungs and then snap his neck for good measure, he heard something. It was hoarse but it was there.

Rin Okumura, seconds away from death, was laughing.

This had Amaimon stumped and confused. Without thinking, he released a bit of pressure to his neck and the laughs came clearer. Aggravated that Rin wasn't pleading for mercy, but intrigued at the odd behavior, he silently watched his younger brother, not know if he should finish him or not.

"I… I pity you…"

Amaimon gazed wide eyed. What?

"I mean, it's sad… when you think about it… all… you know is… pain… and… harming others… I bet you've never had a real friend… someone to rely on… someone to care for… protect… share memories with… you never had any of that have you?" He managed to grin and stare down at Amaimon like he's a clueless child. "Shame… I guess we really are different… but as I said before… strength isn't everything… and even if humans are weak, they possess things that you can only dream of having... I never realized that the life of a demon is a sad and lonely one… so for that… I pity you…"

"SHUT UP!"

Amaimon raged, releasing Rin's neck to punch him in the stomach. The half-demon coughed in pain. The punch also broke the shelf behind him to splinters and deep cracks on the wall behind it could be seen. Amaimon punched him again, no longer caring about his brother's orders, just wanting to see Rin become nothing but a bloody pulp. Pity? How dare he pity him? He's the Earth King! He should fear him!

"I'll kill you! I'LL KILL YOU! I'LL SMASH YOUR SKULL TO PIECES AND TEAR YOUR LIMBS OFF YOU SORRY EXCUSE OF A-"

CRASH!

SHATTER!

SLAM!

Unbeknownst to either of them, the box of elixirs fell on both of them, the glass breaking and spilling its contents on both of them. After that, the top half of the destroyed bookshelf caved in and toppled on them, crushing them to the floor where more of the spilled potions mixed together below them. A puff of pink smoke later and…

Well…

Yeah, you get it.

_ …. .… .… _

Feeling the anger surge back into him when recalling those events, he plopped the lollipop back into his mouth. The taste of the fruity flavor and sugar only calmed him slightly, but it's what he needed. It's best to not to show any hostility, not right now at least. He'll vent his frustrations on some demons in Gehena after he receives his punishment.

"Stand up."

He almost didn't catch that, being lost in his thoughts, but he stood. Mephisto also stood and calmly walked around his desk. He stopped, standing face to face with Amaimon with hands behind his back and his face oddly even.

Most likely he'll get another beating for his misbehavior. This isn't the first time he's received it, he's gotten plenty from some of his older brothers and Satan himself once. Of course Satan's punishments were the very worst and all his brothers new it. After receiving one from him, he vowed to avoid getting one again.

Nothing happened for a while and Amaimon stood confused, wondering why his brother hasn't done anything yet. He was about to ask until Mephisto placed two fingers on his forehead and began chanting. It was in the Gehena language, however the words he used seemed ancient for the Earth King could not understand it fully. Something about suppression… Before he could analyze it further, he suddenly felt drained. His limbs felt heavy and his senses dulled. Little by little he felt himself grow weaker and weaker.

He now understood. He understood when he tried to lift his arm. It no longer carried the familiar gripping force he was used to. It was now simply skin and bone; won't even lift a boulder.

Mephisto stopped his chanting and Amaimon found himself on his knees, as if his legs have lost all of its energy from standing. His eyes drooped, ready to close. He's never felt so tired in all his life. Sleep sounds really good right now.

"I have sealed your powers little brother. I find it as a necessary precaution for what I have planned for you." Amaimon couldn't see his face. He found it tasking to lift his head so he could not read his brother's expression. "But not to worry, if all goes well and you do as you're told, I'll lift the seal. But, if you disobey me again, I'll leave you to rot in Gehena."

Amaimon didn't have it in him to speak. All together he was tired, speechless, and a rare feeling he identified as scared. Amaimon was scared. Terrified even. His powers are gone, meaning he's no longer a Demon King. He's been reduced to a low class demon, or worse, a human.

This has to be the worst form of punishment ever given to him, even worse than Satan's. And Mephisto's not done with him yet.

As he slips into the darkness of his consciousness, Amaimon could only think of one thing.

Of how all of this was Rin's fault, and that one day, he'll make him pay.

AN: And the adventure begins! Sort of. Wonder what's gonna happen to Amaimon…

I don't know jack squat about alchemy or potions but it seems like an elaborate excuse to make the guys turn into girls okay? Besides Mephisto can definitely master alchemy if he wants to… Also he's powerful enough to seal a demon's powers. If he could do it with Rin, well he should be able to with Amaimon as well.

Why is he doing this you ask? Hell if I know, the fabulous bastard's a schemer.

Anyway, let me know what you think and I apologize if this starts out confusing. Please fave and/or review and I'll cook up a new chapter soon!