A/N: So, my obsession is now Vampire Knight. The boys are just too hard to resist, and them being together is even harder. Also, ever since that picture of Alice!Zero, I've been pondering over the idea of a gender-bender KanamexZero fanfic. Well, here it is. Enjoy :)

Please note that any biology and chemistry information mentioned in this fic is my idea alone, they may not be scientifically accurate. After all, this is a fanfiction.

Disclaimer: Vampire Knight belongs to Matsuri Hino. I was just playing with the characters and make them suffer :)

Aido was extremely bored.

It was the weekend, which means there was no class, which means he had absolutely nothing to do. The blonde genius was sprawled out on his bed, looking at the curtained window upside-down as his head was hanging off the bed. He was probably one of the few students to remain in the dormitory this hour. The afternoon was quickly approaching, signaling that almost all Night Class students were out town for some time away from the academy. Apparently, Aido found such activities provide no significant benefit for him, as he'd rather stay behind and do more meaningful things such as researching on blood tablet development or carrying out some experiments. Speaking of experiments, lately, the aristocrat had been tampering with gender deciding factors, a.k.a estrogen and testosterone. He had discovered that given some appropriate catalysts along with a suitable environment, bio-chemical reactions could happen and somehow change the DNA patterns of the two hormones, inverting them. Estrogen would become testosterone and vice versa. Aido was on his way to develop a potion acting as a decent catalyst for such phenomenon to happen. However, said potion had yet to be proven effective due to the fact that no vampire would volunteer to be tested on, "especially by you, Hanabusa" as Kain's words. The blonde must admit that some of his…weird experiments had become quite the disaster in the past, some cleaned up by a dangerously calmed Kaname-sama…But all of his experiments weren't meant to do others harm! Like that time he cured Shiki from a temporary anorexia nervosa, which ended up in the boy eating pokey a whole week non-stop (actually he couldn't stop), gaining quite some unwanted weight and draining Rima's wallet…Never mind that. There was this time he tried to turn coins into cats, it was just to take care of the annoying rats lurking around the dorm…although it resulted in a horde of untamed cats trying to tear out curtains, sofas and knock off various vases…Okay, Aido swore he wasn't going to test this on anyone.

The noble finally decided to get up from bed and finish his never – to – be – tested potion. Or he could always use some rats…

Zero Kiryuu sighed as he walked towards the Headmaster's office with hands shoved into his pocket. For a whole day, the sun had been constantly radiating its scorching heat, showing no mercy towards the Day Class students who never seemed to have a summer uniform_ which dear Chairman hadn't thought of. Zero could feel his heated body soaked with disgusting perspiration, and as much as he hated to admit it, the consistent sun shine did in fact affect his sensitive vampire skin, seeing that he now had a small sunburn on his neck. The hunter finally arrived at his destination and opened the door that separated him and his adoptive father.

"What did you call me for, Chairman?"

"ZERO-KUN MY DEAR SONNNNNNN!"

He was immediately pounced on by said energetic adoptive father. However, blessed with years of experience and quick vampire reflex, Zero managed to dodge in time as Chairman Cross lost his balance and met the door with his face. The hunter quickly did a graceful backflip when the man lunged for him again, following by a lightning fast cart wheel, trying his best to get away from the bouncing Chairman. God does this man ever give up? Wanting to stop this game of cat and mouse, Zero did the only thing he could. He punched the Chairman.

The punch sent Kaien Cross across the room, but when he recovered from it with a nosebleed and a lump on the head, a sense of sanity had returned to his eyes.

"What did you call me for, Chairman?" Zero repeated his question monotonously as if their little physical training session had never taken place.

Chairman Cross adjusted his glasses calmly and stood up, placing a hand on the hunter's shoulder "Zero, my son, after all those years living under the same roof with you, I've come to understand that you are a very kind boy at heart. Every day, I am proud to see you become more and more mature and responsible, also more carin-"

"Just get to the point."

"My, doesn't Kiryuu-kun feel happy to hear my compliments-"

"You are just flattering me so that I'll accept to do something I don't want to. "

"Hah…Kiryuu-kun always sees through me. Can you go to the Moon Dorm and hand these documents to Kaname-kun?" The chairman finally gave up beating around the bush.

"Where is Yuuki? She would be glad to accept a task as long as it involves that bloodsucker…"

"I sent dear Yuuki on some other business earlier, you're the only one I can rely on now, Kiryuu-kun."

Zero just nodded grumpily and took the file. He quickly headed for the door; hand reaching for the awaiting handle as fast as possible…Chairman Cross was starting to have that familiar look in his eye.

"I know my son would kindly do me a favor-"

Again, the Chairman was hit in the face with a closed door.

Finally, he succeeded! Aido did a mental victory dance as the chemical substance he was watching turned into a watery blue color. After spending the entire afternoon mixing different vials with a painstaking level of delicacy, his gender bender potion was finally completed. He needed to test it! I'm sorry Kaname-sama, I'm sure this wouldn't hurt anybody! But still, should he? His experiments always ended up in a mess, and Kaname-sama wasn't pleased each time. At all. But a female Kaname-sama – a female Kaname-sama… Aido shook his head in embarrassment to stop the tempting mental images that had started to flood into his mind. Well, maybe he would have to do with rats, after all.

The blonde carefully held the vial in his hands and walked down the hall. The rat nest was somewhere near the end of this hall, in a dark corner where no one paid attention to. Those sneaky little bastards. Aido had become their enemy ever since they devoured his cake with an inhumane speed in the kitchen while he went out just to get a spoon. He swore those were no normal rats…A black, moving object caught his eyes. Well, at least those bastards were still good for something: becoming his test subjects. The aristocrat burst into run as he chased the escaping animal with vampire speed. The rat was fast, but not fast enough; Aido reached his free hand forwards at an attempt to capture the black thing, but as soon as his mind registered an even bigger black thing blocking his way, the inevitable happened.

Zero wasn't able to move in time as Aido crashed into him, sending the documents in his hands everywhere. Aido had been running at vampire speed, so the impact was not at all little, knocking both of them down the stairs. The hunter grunted painfully as the marble stairs dug into his back; his fall cushioned Aido's. They ended up a messy tangle of limbs on the floor after the unexpected flight downstairs. Before Zero was able to recover, he felt a funny smelling liquid trickling down his face.

It took Aido sometimes to overcome the initial surprise, and he quickly pushed Zero away as soon as he did. The aristocrat stood up and brushed his clothes as the ex-human gave him a death glare

"Do you ever pay attention to where you are going?" Zero asked angrily

"You could have dodged that, mister vampire" Aido quickly sent the prefect a sarcastic retort, which only fueled his anger. However, Aido didn't pay attention to what the hunter was saying as he finally realized that the vial was no longer in his hands. His gazed darted to Zero in panic and his suspicion was immediately confirmed: the ex-human's head and uniform was dripping with the potion.

"Oh my God, you ruined my whole work!" Aido almost roared at the loss. All of his time, his carefulness…was now thrown away. Just because Kiryuu had to be in the wrong place and at the wrong time.

"And now you are blaming me? You dumped this thing onto my face, and God knows what it is!" Seriously, the funny scent was getting even funnier, it smelled like…Yuuki. Feminine.

"It's my gen-"Aido paused at midsentence as another thought appeared in his head. Wait, maybe this wasn't as unfortunate as he thought. Actually, Kiryuu had just unknowingly become his unexpected test subject. Yes, maybe for once things were going the way he wanted. Aido did an evil mental smirk that surprised even himself.

"It's your what?"

"Oh, it's nothing, just some random water." The noble answered smoothly, mental smirk still in place. God he was so brilliant.

Before Zero had the chance to press at the question, a collected voice rang out from above the stairs

"Did anything happen here?" Kaname had heard the crash earlier, however, he didn't expect himself to be amused at the scene in front of him: Aido standing with a disturbingly faraway look in his eyes; and Zero, hmm Zero, was sprawling on the ground in a suggestive pose, with liquid dripping from his hair and wetting his now quite transparent shirt.

"Kaname-sama! Nothing happened here Kaname-sama, just an ungraceful person who doesn't even know how to dodge when someone is running into him." Aido glanced meaningfully at the now fuming hunter.

"You idiot, you are the one to run into me in the first place! You should watch yourself more carefully before blaming someone else!"

"Well, if it's not for you walking ther-"

"Now now, Aido, you should reconsider the situation. It's not entirely Kiryuu-kun's fault to not be able to dodge in time, you were the one who caught him in surprise." Kaname calmly analyzed the problem, and pointed that out for Aido.

"B-but Kaname-sama…" Aido looked at the pureblood pleadingly.

"I think you are the one who should apologize first, Aido." Kaname spoke with a tone that meant 'this shall be finished here. and. now'

"Yes, Kaname-sama" Aido turned to Zero bitterly "I'm sorry for bumping into you" unintentionally_ he added mentally. Still, he needed to be nice to Zero so that he would have the chance to witness his potion taken effects.

"It's okay." Zero answered quickly, wanting to leave this place as soon as possible. He regarded Kaname with the usual hatred in his eyes "Chairman Cross sent me to deliver those documents to you." He pointed at the papers that Kaname had already gathered earlier.

"Yes, seeing that I'm now holding them, your task is finished." Zero took that as 'you've done your job, now go' and started to turn away, trying to force back down his throat the retort that threatened to spill out. But even in a thousand years, he would never ever expect Kaname's next action. The pureblood grabbed his arm, leaning closer to his face_only inches were left between them, and Zero could nearly taste Kaname's breath as they touched his trembling lips. This fact kept him frozen in place, unable to just follow his screaming will and punch the bloodsucker's face in. Kaname slowly inhaled, savoring the essence clinging to the hunter's body. The scent…it was so captivating, if not alluring…so feminine that it stirred up the deepest desires within him. The longer they stayed in this position, the need to just ignore everything and dominate the hunter became harder to resist. Ah…He could see a glimmer of fear in the ex-human's closely guarded eyes. Yes, you should fear me, for I am going to own you, body and soul. Kaname leaned in closer and practically purred into his ears "Thank you, Zero" in a voice coated with burning desire.

To Zero's horror, Kaname started to lick his neck slowly, sensually in a seductive manner.

His control broken, the hunter sent a fist aiming for the pureblood's face.

Aido sighed as he stepped out from the bathroom, the heat of the bath still radiated from his body. He was torn between triumph and fear. Triumph, for his potion had taken effect so fast, and so successful. As the testosterones slowly turned into estrogens and vice versa, the body of the host would release a distinct smell of the sex they were turning into, which would trigger the natural instincts of the opposite sex, if they happened to catch that scent. His mind registered this as soon as he sensed the waves of lust emitting from Kaname-sama, and his little display with Kiryuu. What happened after that was pretty much a blur in his mind. Aido almost tore the hunter's throat out right then and there for landing such a blow on his Kaname-sama's beautiful face, but the pureblood stopped him, and silently watched Kiryuu bolting out of the dorm. Kaname-sama then just returned to his room without asking a single question. This unnerved the blonde noble, as he didn't know whether Kaname-sama had suspected him or not, as he might have heard his and Kiryuu's little bicker to find that Aido had almost slipped up the word 'gender-bender'.

Well, the good thing was, his potion did work, and effectively at that as far as he had seen. Now, a real smirk twisted the aristocrat's lips. Just you wait Zero Kiryuu, that was only the first stage. Soon, there will be more surprises for you…

Aido felt so evil.

Zero slowly slid down his closed door, and buried his face in his hands. He sighed in frustration when he wasn't able to cool down, his cheek still flushed with a deep red color. What the hell did that bloodsucker think he was doing? The sensation of being licked so sensually was still very much real on his neck, which was becoming even warmer as he remembered the feeling. Also, that feeling of the pureblood's breath on his lips. Zero shivered, despite his protesting mind. He tried to scold himself: why are you so worked up? Maybe he was just playing with you. You knew that, that's why you punched him. Yes, it had been satisfaction he felt when his fist connected with Kaname's face. He deserved that, for suddenly acting like a lion in heat_ the hunter swore it was hunger he saw in the pureblood's eyes.

Deciding not to think about this anymore, Zero stood up and headed for the bathroom. Maybe tomorrow he would straightly ask the bloodsucker the reason he did that, like a man, not pondering over it like some goddamn girl.

Little did the hunter know that after receiving his punch, Kaname had an abnormal daze in his eyes, as if he had snapped out of a dream he had unintentionally had.

- To be continued -