A/N: …Shut up. I'm writing this for entertainment.

Warnings: There will be homosexuality, SPOILERS for the manga and third book, lots of unneeded drama, violence, swearing, occasional crack, Kurama topping (in case that bothers you), a-little-too-happy-Mukuro (because it's always funny), and of course me, being one of the shittiest authors ever (see, there's already swearing in the WARNINGS).

Pairings: [KuraHi], hints of [YusuKei], [KuwaYuki], [canon HP pairs], implied [MukuYomi]

~oOo~

"Why am I here?" Hiei asks as soon as he enters Koenma's office, clearly irritated, but that's normal for the short-tempered fire demon. Mukuro, Yomi, Koenma, and Kurama are seated in the room, but by the looks of it, Koenma and Kurama have only arrived moments before.

"A mission!" Mukuro says happily and Hiei only thinks that she sounds way too glad about it. He groans internally because he just came home from a mission an hour before. "I know you've been injured, so I asked Yomi-chan—" at this, Yomi sighs and groans at the nickname "—to let me borrow Kurama to take care of you for the next year!"

"Year?" Hiei turns to Koenma, Kurama, and Yomi in askance of what the hell is going on. Kurama shrugs helplessly, signaling that he doesn't know yet. Yomi subtly points to Koenma and Koenma merely looks around.

"The mission is about sending the old Reikai Tantei to a magic school called Hogwarts," Mukuro chimes in helpfully. "The full details will be explained once your two friends arrive."

"They are not my friends, dammit!" Hiei almost immediately forgets about the rather familiar word—Hogwarts—in favor of snapping at Mukuro for even referring to the Reikai Tantei as his friends.

"Oh, sorry. Should I say the people who risked their lives for you? Or the people you risked your life for? Or the people you trust? Or the people who care for you? Or the people you care for?" Mukuro replies cheekily.

Before Hiei can retort, the door is opened and Yusuke, Botan and Kuwabara are running in, their moods almost as foul as Hiei's is. "The hell do you want, toddler?" Yusuke snaps before he notices Yomi and Mukuro. "Oh, hi Mukuro, Yomi."

"I've asked to borrow Hiei and Kurama for a year-long mission along with you two," Koenma says quite cheerfully. "Since this will be relatively easy, I'll let you consider it a break of sorts. And Hiei was injured on his last mission—" Hiei growls at this "—so I think it'd be a good idea! Mukuro and Yomi have agreed already."

"Who's the client?" Kurama inquires, as patient as always, as he is the only one of the Reikai Tantei who isn't shouting or pissed. Well, Kurama might be pissed, but when it comes to the tricky kitsune, nobody could tell…well, except for Hiei, and Hiei can tell that he's beyond irritated at this point, with the barely noticeable strain of anger in Kurama's cool and suave tone, the way his demonic energy is twisting in the air, the way Kurama just barely spits out the question.

"Albus Dumbledore," Koenma answers without missing a beat. It seems he hasn't noticed the waves of anger radiating off of the kitsune.

Hiei recognizes the name and barely flinches but he knows Kurama's noticed it and the look in his green eyes tells Hiei that he's going to ask him about it later. The fire demon's red eyes narrow, and he wonders what the old man is up to now.

"He wants you four to go to his school, Hogwarts, a school of magic, as protection since a man called Sirius Black is on the loose, and there are dementors around the school." Hiei's eyes narrow even further. "Apparently, their Ministry of Magic has sent them there to find the man. However, Sirius Black is actually innocent of killing the seven humans at the scene, and was framed. Dumbledore wishes for you to attend his school as professor's assistants and work undercover for the year."

Koenma clears his throat before continuing. "Dumbledore will owl me the items you'll need soon, and you can head to Leaky Cauldron and Diagon Alley tomorrow. Also, your demon statuses will be known."

"What the hell do you mean by 'owl'?" Kuwabara asks, glaring at Koenma. "And how can we tell this isn't all some huge joke?"

"The wizards send all their post by owl," Koenma responds. "And no, this is not some complicated joke. I will be expecting you tomorrow to send you to London; you'll need to read up on everything before you go. You'll have a week." The toddler makes a shooing noise and Mukuro and Yomi push the four out of the room before shutting the door behind them with a loud bang.

"This sucks," Yusuke complains, slouching dejectedly.

"I have to say, I'm thinking along the same lines," Hiei agrees, "but I probably would have voiced it in a less crude way."

"No, I mean, how am I supposed to explain this to Keiko? She's going to be angry at me for canceling again!" Yusuke moans, recalling the torture the human girl puts his poor cranium through.

"The truth," Botan tells him. "Don't lie to a girl, she'll always find out the truth sooner or later."

"Come on, Hiei, let's go get your wounds looked at." Kurama drags him off, definitely wanting to question Hiei's strange reaction, but fortunately for Hiei, the rest of the Tantei follow after.

~oOo~

Tomorrow finds the Reikai Tantei in Koenma's office once more, Mukuro and Yomi absent this time around. There's an old boot on Koenma's table and Hiei sighs. A Portkey…he hates those blasted things!

"The bag," he drones, holding out a hand to Koenma for it. Koenma looks at him as if he's gone crazy. "There are four bags on your desk. I assume we'll each get one. So the bag."

"Ah! These are the books that you are to read." He passes a rather large book bag to each of the four, and Hiei looks into the leather bag, bored. It seems that the old man hasn't changed the books in the school yet. And it seems these are his old books, with a few new additions for Care of Magical Creatures. Hiei feels the quiet and subtle power coming from the wand in the case he borrowed from Kurama for the time.

He's already worked out just why Dumbledore wants the Reikai Tantei. If the old man is still as wily as Hiei remembers, then he'd most certainly want some people—or demons, in this case—who could be eyes and ears in each house. Hiei and Kurama are the only ones who can survive in Slytherin, but Kurama is the only one smart enough for Ravenclaw. Thus, even if Hiei was in Gryffindor at the beginning, he has to join Slytherin. Yusuke is the most qualified for Gryffindor, and Kuwabara is the most suited for Hufflepuff. Interesting.

"Touch this boot," Koenma says, pointing to the boot on his table. "I hope you've packed everything? Good. Touch it, and you'll be sent to Leaky Cauldron. Tom will show you how to get to Diagon Alley from there."

"Is this some kind of joke?" Yusuke growls but Hiei throws the boot at his face and it bounces off of him and hits Kuwabara and drops onto Kurama's foot. Then they all start to disappear.

Hiei lands on his feet, feeling nauseated as his feel hit the ground, but he forces his feelings of sickness down. The wizards in the room all briefly look at them before turning back to their own things, used to this kind of entrance.

"Nick trick," Yusuke manages to say to Hiei, clutching his stomach. He turns to the nearest wizard and asks weakly where the bathroom is. The wizard points and he runs towards it, Kuwabara chasing after him, looking queasy. After a moment, Hiei's sharp ears can hear the sound of pained retching.

"What about you?" Hiei asks Kurama nonchalantly, referring to the traveling as they head to Tom to get the keys for the rooms.

"I'm perfectly fine. Slightly disoriented, but fine." Kurama pauses. "And you?"

"Fine. Just want to throw up a bit, but it'll pass."

Kuwabara and Yusuke stumble out of the bathroom, looking a bit better. "Hey, did you get the keys?" As a response, Hiei throws a pair of them in their faces, heading upstairs to the room that they'll all be sharing.

The room is nice and spacious with four beds with curtains obscuring what is going on behind them. A door that Hiei assumes leads to the bathroom is situated near the entrance and immediately, Hiei sits down on the nearest bed, setting his things next to him.

Kurama takes the bed nearest to his, Kuwabara heading for the farthest one from Hiei. Yusuke sighs but takes the last bed anyway.

It's only four in the afternoon, but the time differences between Japan and England are vast. Hiei takes out the books and sets them out on the bed, picking up a book at random and opening it to the first page. He recognizes it briefly as the third year Potions book, which is the year they'll be bunking with. The fire demon sighs and flips through the pages, bored, skimming over the familiar text before his eyes.

An hour in, Hiei's gaze slides over the room. Kuwabara is reading through the first year Transfiguration textbook, frowning at the complex Latin words. The only reason why he can even understand the words in the book is because of a bracelet that had a translation spell on it. Yusuke is lying on his back, the first year Defense against Dark Arts book raised above his face, occasionally flipping the page. Hiei can tell he's actually reading it, even with the bored look on his face. Kurama, being the clever kitsune he is, is already reading the second year Potions book, carefully recording data. As Hiei's red eyes land on him, Kurama's green eyes slide sideways to meet his gaze.

Hiei groans and closes the book with perhaps more strength than he needed and sets the book on the bed. The three others in the room are startled—with the exception of Kurama—at the sudden noise and glance up at Hiei as he jumps off the bed and heads for the bathroom.

"Hmm? Is there something wrong, Hiei?" Kurama calls after him, but he only gets a slammed door and a click to signify that he's locked the door as a response.

Hiei glares at his reflection, sitting down in front of the enchanted mirror in the bathroom. He good to honest hates this, and he really wants to kill Dumbledore for picking him for this mission. The fire demon heads to the sink and picks up a towel to wipe his face with cool water, despite his normal dislike for it.

After doing so, Hiei comes back out, feeling a bit refreshed and resumes his rereading of the third year Potions textbook, flipping the pages.

~oOo~

Surprisingly, Kuwabara and Yusuke actually manage to finish all seven books and perform most of the spells relatively well within a week. A few days ago, they'd gone to fetch their wands, but Hiei had made an excuse to go later by himself because he already has his own wand…and he doesn't need them asking about why.

"We're heading to Hogwarts tomorrow," Kurama tells them, "so we'll need to be ready. An owl came by this morning, as you know, addressed to all of us. It says that a man, Dumbledore, I assume, will come pick us up at three o'clock so we can get to Hogwarts to meet the teachers we will assisting."

"Okay," Yusuke mumbles, his face buried in a pillow. It's ten o'clock and all of them just want to sleep. "As long as it's not another one of those damn Portkeys and I'll be peachy."

Hiei agrees and draws the curtain shut and goes to sleep.

~oOo~

The next day, at three o'clock, they check out of the Leaky Cauldron and wait for Dumbledore to pick them up. Hiei already knows what to expect, and he leans against the wall casually, careful not to irritate his injuries too much. Kurama's already warned him enough times not to.

A sudden crack and Dumbledore is here, with his awful fashion sense. "Hello, sirs. I am Dumbledore. I assume you were waiting for me?"

He regards all four of them from behind his half-moon spectacles. "Jaganshi Hiei. Kuwabara Kazuma. Urameshi Yusuke. Minamino Kurama. Am I correct?"

"Yes. Thank you," Kurama replies, polite as always. He seems to study Dumbledore carefully with those emerald green eyes of his.

"Now, I will be Apparating you to Hogwarts. I've momentarily dropped the Apparating rule in Hogwarts for me, and four others only. So, if you don't mind…" Dumbledore holds out a hand, and Hiei rolls his eyes but takes it. After they awkwardly hold hands—kami-sama, they're okay with saving each others' lives but not holding hands…!

They reappear in Hogwarts's Great Hall, and Dumbledore waves his wand to replace the Apparating barrier. "I'll let you meet my fellow professors. Come with me now." Hiei follows the old man along with the rest of the Reikai Tantei, knowing where he's taking them.

They enter the Headmaster's Office and Hiei is immediately greeted with a faint but warm, nonetheless, smile from McGonagall. It really has been a long time, because Hiei can tell his old House Head is definitely getting older.

"Good afternoon, professors. We are glad to bring four new professor assistants to our school. Please welcome Hiei, Kurama Minamino, Kazuma Kuwabara, and Yusuke Urameshi," Dumbledore says formally, smiling.

Introductions go around, and Hiei recognizes all of them. It seems that Dumbledore has not changed his staff, but he realizes that the Defense against Dark Arts post is empty. Based off of Kurama's look of curiosity, he knows the kitsune's noticed it too.

"Hey, old man, where's the Defense teacher?" Yusuke asks, bored, ignoring the scandalized looks from the professors around them.

"Ah, you've noticed, mister Urameshi. He's riding on the train with the students," Dumbledore answers kindly. "As you should know, you will be staying the in rooms of your third year housemates."

They all nod.

"Professor McGonagall, Mister Yusuke Urameshi will be your Professor's Assistant. Professor Sprout, Mister Kazuma Kuwabara will be your Professor's Assistant. Professor Flitwick, Mister Kurama Minamino will be your Professor's Assistant. Professor Snape, Hiei will be your Professor's Assistant."

McGonagall looks slightly put off at this, Flitwick and Sprout seem content with their assistants, and Snape is absolutely livid, but he's doing well to hide it.

"As you should all know, two of these are older than me and demons. One is half demon, and the other is fully human." The professors nod.

"Then you are all dismissed. But please be civil with your new partners, and socialize with them for a bit. You may go to your respective houses for now." Dumbledore smiles gently again and his bright eyes twinkle as the Reikai Tantei and their new partners head outside in pairs.

Hiei follows Snape diligently, and until they're well away from prying ears and eyes, they begin to speak to each other. "I seem to recall that we got along quite well, despite me being a Gryffindor." Hiei begins the conversation.

"That is true. You just seemed to dislike the Gryffindors so much…it turned out that you just hated humans in general."

"I recall it took you three weeks to get me to trust your plants, two months to get me to stop throwing knives at you, half a year for me to trust you even a little and a full year for me to trust your potions."

They continue to walk in companionable—kind of—silence and Snape stops abruptly. "This is your dorm." Hiei nods and opens the door, heading into it and setting his things down on the only bed that smells unused.

"I'll see you some other time, Professor."

"And me to you, assistant."

~oOo~

The next day, at dinner, Hiei is heading down to the Great Hall and he sits down at the Slytherin table, ignoring the strange looks he's getting for his attire. But he's not the only one, since Kuwabara, Yusuke, and Kurama all do not have uniforms.

Dumbledore begins his speech and Hiei sighs, props his head on his hand, and tunes it out, turning the other way. He already knows everything that's going on anyway.

He only pays attention when the Reikai Tantei's names are called. "…for Gryffindor, we have Yusuke Urameshi." Yusuke waves and grins brightly at the looks sent his way. "For Ravenclaw, we have Kurama Minamino." The kitsune merely smiles his mysterious and hidden smile. "For Hufflepuff, we have Kazuma Kuwabara." Kuwabara just smiles sheepishly. "And last but not least, for Slytherin, we have Hiei." Hiei shrugs, rolls his eyes, and turns away once more.

"This year, they will be helping your heads of houses during their classes, and after classes, will be teaching Demon Studies. As they work with demons as their job, they are experts in the subject. However, please do not discriminate them for their job, since they do have the authority to give you detention and make you lose house points."

Dumbledore claps. "You may eat now." Food appears on the table immediately.

"So, who are you? Probably a pureblood." Hiei sighs and puts down the chopsticks he'd just grabbed moments before. He turns to the speaker, a silver-blonde.

"Hiei. If you were listening to Dumbledore's speech, then you should know that. Also, I am quite the opposite of pureblood. Worse than what you might call a muggleborn." With that, Hiei picks up his chopsticks again and picks up something to eat, pleased to see that there are Japanese dishes amongst the English food.

The silver-blonde scoots a bit away from him. Hiei snorts in amusement, nearly choking on his food and takes a sip of water, thankful that the clear substance is an option. Hiei doesn't like pumpkin juice at all.

"What are you laughing at?" the blonde demands angrily.

"Your retarded expression," Hiei replies dully without missing a beat. "You're one of those Malfoys, aren't you? The new pureblood family that's risen? I don't care much for purebloods." He sighs and sets his chopsticks down again and swings around. "If all you're going to do is irritate me, I have better things to do. I don't remember Slytherins being this irritating."

The boy opens his mouth as if to say something but Hiei's already standing, wincing slightly when he pulls on his wound. Honestly, what did that stupid lower S-class demon do to his wound…? He'd have to talk to Kurama about it.

Hiei's out of the Great Hall quickly, and he's heading down to the Slytherin dormitories. He hates this.

~oOo~

Yusuke sees Hiei stand up stiffly and head towards the exit of the Great Hall and he pauses in his eating, contemplating. "Hmm. I wonder who shoved a stick up his ass?" he wonders aloud, and the girl known as Hermione Granger looks scandalized.

"Language, Urameshi!"

"Eh. I don't care much for language." Yusuke waves his hand dismissively. "But honestly, he doesn't need more stress. He's got enough on his plate already."

The ginger-head scoffs. "Who cares? He's a Slytherin anyway."

The half-demon raises an eyebrow. "Are the relations between the two houses really that bad? I mean, sure, Hiei happens to enjoy beating the living shit out of me as a greeting but it's the only way he knows how to show affection. And I just don't understand the relationship between Kurama and Hiei."

All of the wizards who can hear him goggle at him as if he's grown a second head. "What?" Yusuke asks, confused. "It's not as bad as when I trap Kuwabara on the floor until he begs for mercy. Hiei just makes me eat dirt and then walks away after saying 'that was a good match'."

"He beats you?" the boy with black hair and green eyes—Harry Potter—exclaims, gaping.

Yusuke blinks. "Yeah. I mean, I know that he's small and all but he packs a huge punch. Like, he can kick mine and Kuwabara's asses without trying when it comes to physical strength." Then it dawns on him. "Oh! I think you're using the wrong definition of 'beat'."

Ron tilts his head. "What are you bloody talking about?"

"I'm saying that he can beat me in a spar easily. He'll shove me face first into the ground and then release me before walking away. I can put up a pretty good fight, but it doesn't usually last more than an hour. By that time, Hiei actually breaks a sweat and most of the time he loses his cloak and shirt."

"Okay…you need some serious mental help, mate," Harry says nervously, laughing sheepishly.

Yusuke grins. "That's what Genkai says, and then sends me climbing up the cliff with only my hands while there is a pair of iron balls attached to my legs. My record is fifteen seconds."

He treasures those ridiculous looks of surprise on their faces.

~oOo~

A/N: I had a hard time ending this chapter here. XD Do you have any questions? Review/PM me and I'll try to answer without spoiling too much for you.

By the way, in this fic, I will rank them in terms of PHYSICAL strength as following: Hiei, Yusuke, Kuwabara, and Kurama. Kurama isn't weak, physically, but he isn't as strong as he manipulates plants to do his bidding.

For going all out, I rank them as following: Yusuke, Hiei, Kurama, Kuwabara. Again, Kurama does not make the list at the top because he will not be able to go into Youko's form in the duration of this fic because he looks completely different. Even if he were to go into Youko's form, he would only be equal to Hiei. Yusuke, being Raizen's descendant and all, is the strongest, obviously and it's partially because of his status as the main character. As Kuwabara is the only one who is completely human, he remains at the bottom. This is not to say he is weak.

For wits/brains, I rank them as following: Kurama, Hiei, Yusuke, and Kuwabara. Pretty self-explanatory here.

For houses, I believe that Hiei and Yusuke are Gryffindors, Kurama is a Slytherin, and Kuwabara is a Hufflepuff. However, Hiei does mention at the beginning of the fic that only he and Kurama could play it off as Slytherins, but Kurama is the smartest of them all, thus he needs to go into Ravenclaw. Hiei joins Slytherin, and Yusuke and Kuwabara go into their respective houses.

Hiei is most certainly a Gryffindor. He probably wouldn't survive in that house for long, since he does like sleeping—has anyone else noticed that he tends to pass out after a battle a lot?—and he would lump them as "idiots and fools". However, he does care for Yukina way too much—sister complex?—and Kurama mentions to Yusuke that "he's going through a tricky change. It appears that he is beginning to like you." Everything he does is mostly just a defense mechanism, because if you know the basic outline of his past, it's pretty bad. I drew my conclusions upon this.

Yusuke is a Gryffindor. End of story.

Kurama is a Slytherin. Being a fox demon/kitsune, he is incredibly sly, but in the series, he is shown to be more knowledgeable and clever because he's mellowed out a little, along with the fact that it's more of an act than anything else. He was a thief in his past as Youko, and while some may think Youko and Kurama are two separate entities within the same body, they are not. They are the same person, just two sides of him or her. The Kurama in the series is a front, and Youko Kurama is his true self in my opinion. Therefore, I believe he is a Slytherin. (Please note that Slytherins are not evil.)

Kuwabara is a Hufflepuff. This is not because he comes off as dumb in the series; not all Hufflepuffs are, and they merely value chivalry and loyalty above all else. Kuwabara is a prime example of that because he tends to treat women quite well and has a code of honor. He refused to fight females throughout the series if you've noticed and he cares for Yukina way too much. He's loyal to a fault to his friends, and despite them making fun of him a lot, he still sticks by them. If that isn't a testament of loyalty, I don't really know what is.

I hope that clears things up for you! :D Just to say, I have plenty of things planned for this fic, so you should expect more coming around…my other YYHHP crossover was merely a brainstorm—aka a plot bunny that leads nowhere. I've thought about this one a lot and I have the ending planned out. Kind of. Not really. SHUT UP. XD