A/N: This is my first crossover, specifically a YuGiOh/Harry Potter crossover. Hope you enjoy it! This is the first book and if it is popular, I will do the next one. If that's popular, I'll do the next and so on.

Summary: What if Ryou and Harry were best friends, before he knew about Hogwarts. What if Ryou could wield Shadow Magick, herself? What if Ryou was a powerful shadow mage? What if she was there to help Harry throughout his years at Hogwarts, but at a distance?

Warnings: Fem!Ryou, AU, None of the original HP couples, takes a lot of text from original Potter book, very long chapters, sticks almost to the original story with a lot of changes, Ron-bashing, Dumbledore-bashing.

Ryou doesn't actually attend Hogwarts.

Chapter One-The Vanishing Glass

Nearly ten years had passed since the Dursleys had woken up to find their nephew on the front step, but Privet Drive had hardly changed at all. The sun rose on the same tidy front gardens and lit up the brass number four on the Dursleys' front door; it crept into their living room, which was almost exactly the same as it had been on the night that Mrs Dursley had woken the neighbourhood, screeching, when she found her sister's son on the doorstep. Only the photographs on the mantelpiece showed how much time had passed. Ten years ago, there had been lots of pictures of what looked like a large pink beach ball wearing different coloured bobble hats-but Dudley Dursley was no longer a baby, and now the photographs showed a large, blonde boy riding his first bicycle, on a roundabout at the fair, playing a computer game with his father, being hugged and kissed by his mother while a pale-skinned, white-haired girl pulled a face in the background-which the Dursley's failed to notice. However, the room held no sign that another boy lived in the house too.

Yet Harry Potter was still there, asleep at the moment, but not for long. His Aunt Petunia was awake and it was her shrill voice which made the first noise of the day.

"Up! Get up! Now!"

Harry woke with a start. His aunt rapped on the door again.

"Up!" She screeched. Harry heard her walking towards the kitchen and then the sound of the frying pan being put on the cooker. He rolled onto his back and tried to remember the dream he had been having. It had been a good one. There had been a flying motorbike in it. He had a funny feeling he had the same dream before.

His aunt was back outside the door.

"Are you up yet?" she demanded.

"Nearly" said Harry.

"Well, get a move on, I want you to look after the bacon. And don't you dare let it burn! I want everything perfect on Diddy's birthday!"

Harry didn't know whether to groan or snicker, so he ended up making an odd sound in between either.

"What did you say?" His aunt snapped.

"Nothing, nothing…"

Dudley's birthday-how could he have forgotten? But then, Diddy? He hadn't heard his aunt use that one before. Harry got slowly out of bed and started looking for socks. He found a pair under his bed and, after pulling a spider off one of them, put them on. Harry was used to spiders, because the cupboard under the stairs was full of them, and that was where he slept.

When he was dressed he went down the hall into the kitchen. The table was almost hidden under all Dudley's birthday presents. It looked as though Dudley got that new computer he wanted, not to mention the second television and racing bike. Exactly why Dudley wanted a racing bike was a mystery to Harry, as Dudley was very fat and hated exercise-unless of course it involved punching somebody. Dudley's favourite punching bag used to be Harry, but he couldn't often catch him. Harry didn't look it, but he was very fast. He was also no longer a punching bag, thanks to his only friend-Ryou Bakura.

It happened one day, when Dudley and his gang had caught him and was about to beat him up and all of a sudden a small, white-haired girl seemingly popped up out of nowhere and said "Pick on somebody your own size, fatty!" She had then proceeded to punching Dudley in the face. He and his gang had scrambled away from the harmless looking girl and ran to their mothers. Ryou had then introduced herself to Harry and told him that she wasn't often violent, but she knew when somebody needed help. That day was the best of Harry's life, as not only did he gain a friend, but Dudley spent the next month walking around with a broken jaw! Just like Harry was very fast, Ryou didn't look it, but she was incredibly strong.

Perhaps it was something to do with living in a dark cupboard, but Harry had always been small and skinny for his age. He looked smaller and skinnier than he actually was (around Ryou's size) because all he had to wear were old clothes of Dudley's and Dudley was around four times bigger than he was. Harry had a thin face, knobbly knees, black hair and bright green eyes. He wore round glasses held together with Sellotape, because of all the times Dudley punched him in the nose, before he met Ryou. Of course, the Dursleys didn't bother getting him a new pair.

The only thing Harry like about his own appearance was a very thin scar on his forehead, which was shaped like a bolt of lightning. He had had it for as long as he could remember and the first question he could remember asking his Aunt Petunia was how he got it.

"In the car crash when your parents died" she had said "and don't ask questions"

Don't ask questions-that was the first rule for a quiet life with the Dursleys. Uncle Vernon entered the kitchen as Harry was turning over the bacon.

"Comb your hair!" he barked by way of morning greeting. About once a week, Uncle Vernon looked over the top of his newspaper and shouted that Harry needed a haircut. Harry must have had more haircuts than the rest of the class put together, but it made no difference, his hair simply grew that way-all over the place. Of course, Ryou had said she like it that way. Harry like Ryou's hair too, especially when she forgot to brush it and it ended up looking like she had bat wings.

Harry was frying eggs by the time Dudley arrived in the kitchen with his mother. Dudley looked a lot like Uncle Vernon. He had a large, pink face, not much neck, watery blue eyes and thick, blonde hair that lay smoothly on his thick, fat head. Aunt Petunia often said that Dudley looked like a baby angel-Harry often said that Dudley looked like a pig in a wig. When this was mentioned to Ryou, she had told Harry to stop insulting 'those poor pigs'.

Harry put the plates of egg and bacon on the table, which was difficult as there wasn't much room. Dudley, meanwhile, was counting his presents. His face fell.

"Thirty-six" he said, looking up at his mother and father. "That's two less than last year."

"Darling, you haven't counted Auntie Marge's present, see, it's here under this big one from Mummy and Daddy."

"All right, thirty-seven then" said D" said Dudley, going red in the face. Harry, who could see a huge Dudley tantrum coming on, began to wolf down his bacon as fast as possible in case Dudley turned the table over.

Aunt Petunia obviously scented danger too, because she said quickly "And we'll buy you another two presents while we're out today. How's that, popkin? Two more presents. Is that all right?"

Dudley thought for a moment. It looked like hard work. Finally he said slowly, "So, I'll have thirty…thirty…"

"Thirty nine, sweetums" said Aunt Petunia.

"Oh." Dudley sat down heavily and grabbed the nearest parcel. "All right then".

Uncle Vernon chuckled. "Little tyke wants his money's worth, just like his father. Atta boy, Dudley!" He ruffled Dudley's hair. Harry imagined a smart arse comment Ryou might have made just then. 'Having more people in the world like you isn't necessarily a good thing, Mister Dursley'. Ryou always put emphasis on their names to show that she was mocking the respect you were meant to show while greeting others using a title.

At that moment, the telephone rang and Aunt Petunia went to answer it while Harry and Uncle Vernon watched Dudley unwrap the racing bike, a cine-camera, a remote control aeroplane, sixteen new computer games and a video recorder. He was ripping the paper off a gold wristwatch when Aunt Petunia came back from the telephone, looking both angry and worried.

"Bad news, Vernon" she said "Mrs Figg's broken her leg. She can't take him." She jerked her head in Harry's direction. Dudley's mouth fell open in horror, but Harry's heart gave a leap. Every year on Dudley's birthday his parents took him and a friend out for the day, to adventure parks, hamburger bars or the cinema. Every year, Harry was left behind with Mrs Figg, a mad old lady who lived two streets away. Harry hated it there. The whole house smelled of cabbage and Mrs Figg made him look at photographs of all the cats she'd ever owned. The only good thing about it was that Ryou would often join him there so they could talk together and he wouldn't have to endure the 'Eternal Torment Of The Cats' as Ryou had dubbed it, alone.

"Now what?" said Aunt Petunia, looking furiously at Harry as though he'd planned this. Harry knew he ought to feel sorry Mrs Figg had broken her leg, but it wasn't easy as he reminded himself that it would be a whole year before he had to look at Tibbles, Snowy, Mr Paws and Tufty again.

"We could phone Marge" Uncle Vernon suggested.

"Don't be silly, Vernon, she hates the boy"

The Dursleys often spoke about Harry like this, as though he wasn't there-or rather, as though he was something very nasty that couldn't understand them-like a slug.

"What about whats-her-name? Your friend-Yvonne"

"On holiday in Majorca" snapped Aunt Petunia.

"You could leave me at Ryou's house" Harry put in hopefully, he had always like it there. Ryou was very creative and a little strange too. Her house was decorate beautifully, but Harry couldn't quite grasp exactly what had made her decide that in the lounge the ceiling would be a good place to put her carpet. They always had fun there.

Aunt Petunia looked like she had just swallowed a lemon.

"Don't think we don't know what you and that girl get up to when you're over there!"

Harry knew the Dursley's didn't know what they did at Ryou's house and he had no desire to see what they thought Ryou and him were doing there.

"I suppose we could take him to the zoo" Aunt Petunia said slowly "…and leave him in the car…"

"The car's new. He's not sitting in it alone."

Dudley began to cry really loudly. In fact, he wasn't really crying, it had been years since he really cried, but he knew if he scrunched up his face and wailed, his mother would give him anything he wanted.

"Dinky Duddydums, don't cry, Mummy won't let him spoil your special day!" She cried, flinging her arms around him.

"I…don't…want…him t-t-to come!" Dudley yelled between huge pretend sobs. "He always sp-spoils everything!" He shot Harry a nasty grin through his mother's arms.

Just then, the doorbell rang-"Oh, Good Lord, they're here!" said Aunt Petunia frantically-and a moment later, Dudley's best friend Piers Polkiss, walked in with his mother. Piers was a scrawny boy with a face like a rat. He was usually the one who held people's arms behind their backs while Dudley hit them. Dudley stopped pretending to cry at once.

Half an hour later, Harry, who couldn't believe his luck, was sitting in the back of the Dursley's car with Piers and Dudley, on the way to the zoo for the first time in his life. His aunt and uncle hadn't been able to think of anything else to do with him, but before they left, Uncle Vernon had taken Harry aside.

"I'm warning you" he had said, putting his large purple face right up close to Harry's "I'm warning you now, boy-any funny business, anything at all- and you'll be in that cupboard from now until Christmas.

"I'm not going to do anything" Said Harry "Honestly…"

But Uncle Vernon didn't believe him. No one except Ryou ever did.

The problem was, strange things often happen around Harry and it was just no good telling the Dursleys he didn't make them happen. Ryou was what was called a 'Shadow Mage'. Apparently, they were very rare magic users to come by. She had told him that it wasn't shadow magick, but another type of magick and she was going to do research about other branches. She had yet to get back to him on that.

Once, Aunt Petunia, tired of Harry coming back from the barbers looking as though he hadn't been at all, had taken a pair of kitchen scissors and cut his hair so short he was almost bald except for his fringe, which she left to 'hide that horrible scar'. Dudley had laughed himself silly at Harry, who spent a sleepless night imagining school the next day, where he was already laughed at for his baggy clothes and his Sellotaped glasses. Next morning, however, he had got up to find his hair exactly as it had been before Aunt Petunia had sheared it off. He had been given a week in his cupboard for this, even though he had tried to explain that he couldn't explain how it had grown back so quickly.

Another time, Aunt Petunia had been trying to force him into a revolting old jumper of Dudley's (brown with orange bobbles). The harder she tried to pull it over his head, the smaller it seemed to become, until finally it might have fit a glove puppet, but certainly wouldn't fit Harry. Aunt Petunia decided it must have shrunk in the wash and, to his great relief, Harry wasn't punished.

On the other hand, he had gotten into terrible trouble for being found on the roof of the school kitchens. Dudley's gang had been chasing him (before he had met Ryou) when, as much to Harry's surprise as anyone else's, there he was sitting on the chimney. The Dursleys had received a very angry letter from Harry's headmistress, telling them Harry had been climbing school buildings. But all he'd tried to do (as he shouted at Uncle Vernon through the locked door of his cupboard) was jump behind the big bins outside the kitchen doors. Harry supposed th wind must have caught him mid-jump.

When he had told Ryou this story and offered the flimsy explanation she had laughed and said "Of course it wasn't the wind Harry. You probably just flew." She had mentioned this in an incredibly casual way, indeed.

But today, nothing was going to go wrong. It was even worth being with Dudley and Piers to be spending the day somewhere that wasn't school, his cupboard or Mrs Figg's house and sometimes Ryou's when he could manage it. While he drove, Uncle Vernon complained to Aunt Petunia. He like to complain about things: Harry, the council, Harry, the bank and Harry were just a few of his favourite subjects. This morning it was motorbikes.

"Roaring along like maniacs, the young hoodlums" he said as a motorbike overtook them.

"I had a dream about a motorbike" said Harry, remembering suddenly, "It was flying."

Uncle Vernon nearly crashed into the car in front. He turned right around in his seat and yelled at Harry, his face like a gigantic beetroot with a moustache "MOTORBIKES DON'T FLY!"

Dudley and Piers snickered.

"I know they don't. It was only a dream." But he wished he hadn't said anything. If there was one thing the Dursleys hated even more than him asking questions, it was his talking about anything that was acting in a way it shouldn't, no matter if it was in a dream or even a cartoon-they seemed to think he might get dangerous ideas.

It was a very sunny Saturday and the zoo was crowded with families. The Dursley's bought Dudley and Piers large chocolate ice-creams at the entrance and then, because the smiling lady at the van had asked Harry what he wanted before they could hurry him away, they bought him a cheap lemon ice lolly. It wasn't bad either, Harry thought while licking it, while they watched a gorilla scratching it's head and looking remarkably like Dudley, except that it wasn't blonde.

Harry had the best morning he had in a long time. They ate in the zoo restaurant because Dudley had had a tantrum that his knickerbocker glory wasn't big enough. Uncle Vernon bought him another one and Harry was allowed to finish the first. Harry felt, afterwards, that he should've known it was all too good to last.

After lunch, they went to the reptile house. It was cool and dark in there, with lit windows all along the walls. Behind the glass all sorts of lizards and snakes were crawling or slithering over bits of wood and stone. Dudley and Piers wanted to see the huge poisonous cobras and thick man-crushing pythons. Dudley quickly found the largest snake in the place. It could have wrapped it's body twice around Uncle Vernon's car and crushed it into a dustbin-but at that moment it didn't look in the mood. In fact, it was fast asleep.

Dudley stood with his nose pressed up against the glass, staring at the glistening brown coils.

"Make it move" he whined to his father. Uncle Vernon tapped on the glass, but the snake didn't budge.

"Do it again" Dudley ordered. Uncle Vernon rapped on the glass smartly with his knuckles, but the snake didn't budge.

"This is boring" Dudley moaned. He shuffled away.

Harry moved in front of the tank and looked intently at the snake. He wouldn't have been surprised if it had died of boredom itself- no company except stupid people drumming their fingers on the glass trying to disturb it all day long. It was worse than having a cupboard for a bedroom, where the only visitor was Aunt Petunia hammering on the door to wake you up-at least he got to visit the rest of the house.

The snake suddenly opened its beady eyes. Slowly, it lifted its head until its eyes were level with Harry's.

It winked.

Harry stared. Then he looked quickly around to see if anyone was watching. They weren't. He looked back at the snake and winked too. If Ryou was there, she would've told him that he was losing it.

The snake jerked his head towards Uncle Vernon and Dudley, then raised its eyes to the ceiling. It gave Harry a look which quite plainly said 'I get that all the time'.

"I know" Harry murmured through the glass, though he wasn't sure the snake could hear him. "It must be really annoying."
The snake nodded vigorously.

"Where do you come from, anyway?" Harry asked, making a mental note to tell Ryou that he could talk to snakes later, in case that would help with her finding the right branch of magic.

The snake jabbed its tail at a little sign next to the glass.

Boa Constrictor, Brazil.

"Was it nice there?"

The Boa Constrictor jabbed its tail at the sign again.

This specimen was bred in the zoo.

"Oh, I see. So you've never been to Brazil?"

As the snake shook his head, a deafening shout came from behind Harry making them both jump.

"DUDLEY! MR DURSLEY! COME AND LOOK AT THIS SNAKE! YOU WON'T BELIEVE WHAT IT'S DOING!"

Dudley came waddling towards them as fast as he could.

"Out of my way, you" He shoved Harry aside. Caught by surprise, he fell on the concrete floor. What came next happened so fast no one saw how it happened- one second, Piers and Dudley were leaning right up close to the glass, the next, they had leapt back with howls of horror. Harry sat up and gasped; the glass at the front of the Boa Constrictor's cage had vanished. The great snake was uncoiling itself rapidly, slithering out on the floor- people throughout the reptile house started screaming and running for the exits. As the snake slid swiftly past him, Harry could have sworn a low hissing voice said "Brazil, here I come, thanksss, amigo."

The keeper of the reptile house was in shock.

"But the glass" he kept saying "Where did the glass go"

The zoo director himself made Aunt Petunia a cup of strong, sweet tea while he apologised over and over again. Piers and Dudley could only gibber. As far as Harry had seen, the snake hadn't done anything except snap playfully at their heels as it had passed, but by the time they were all back in Uncle Vernon's car, Dudley was telling them how it had almost bitten off his leg, while Piers was swearing it had tried to squeeze him to death.

But worst of all, for Harry at least, Piers was calming down enough to say "Harry was talking to it, weren't you Harry?"

Uncle Vernon waited until Piers was safely out of the house before starting on Harry. He was so angry, he could hardly speak. He managed to say "Go-cupboard-stay-no meals" before he collapsed into a chair and Aunt Petunia had to run and get him a large brandy.

Harry lay in his dark cupboard much later, wishing he had a watch and making a second mental note to tell Ryou about the vanishing glass, too. He didn't know what time it was and he couldn't be sure the Dursleys were asleep yet. Until they were, he couldn't risk sneaking into the kitchen to steal some food.

He'd lived with the Dursleys almost ten years, ten miserable years, as long as he could remember, ever since he was a baby and his parents died in a car crash. He couldn't remember being in a car when his parents had died. Sometimes, when he strained his memory during long hours in his cupboard, he came up with a strange vision; a blinding flash of green light and a burning pain on his forehead. This, he supposed, was the crash, though he couldn't imagine where the green light had come from. He couldn't remember his parents at all. His aunt and uncle never spoke about them, and of course he was forbidden to ask questions. There were no photographs of them in the house.

At school Harry had no one, but Ryou (who was an outcast herself, for entirely different reasons, which she had never bothered explaining to him). Everybody knew that Dudley's gang hated that odd Harry Potter in his baggy old clothes and broken glasses and no one liked to disagree with Dudley's gang.

Review please! I spent HOURS on this. And yes, it is meant to be following along the same lines as the original HP books. This took forever and I'm not entirely sure it's good enough to continue. So I will probably continue if I get about 5 reviews (that means more than just one other person likes it).

REVIEW! *Shoves Ryou looking up at you with puppy dog eyes. You know you can't resist!