Disclaimer: I own nothing of Harry Potter and everything recognizable belongs to J K Rowling.

Summary: In an alternate universe Harry Potter grows up having a twin and with his parents alive. It all goes well until the Potters were attacked on Halloween 1981 and his brother Karl is proclaimed by the media as the 'Boy Who Lived' when they are informed that he vanquished Voldemort. Karl in pampered to no end while Harry is treated by everyone as the reclusive and powerless brother of the Boy-Who-Lived. At school, as well as he did at home, Karl basks in his assumed superiority over his brother and shuns him. The rest of the school follows his example except for the clumsy Neville Longbottom, who's Karl Potter's second favorite victim.

Now, fourteen years later, Harry and Karl are in their fifth year. While Karl is prepared and trained to fulfill his destiny and kill Voldemort, Harry and his only friend, Neville Longbottom, try to make it through the final steps of their education before they turn seventeen and can leave the prejudiced, biased and hypocrite Wizarding Britain behind as well as the war that has recently started again. But whatever universe he's in, things don't ever tend to go according to plan for Harry Potter, especially if a meddlesome and scheming Headmaster takes a sudden interest in him when some of his unexpected abilities are discovered.

Warnings: Rated T for some swearing language and for some scenes with a bit of violence at the end of the first book (the fic will be constituted by two books). Will be warned beforehand in those. This is also not a slash story. The main characters are Harry and Neville but the only bond they have is that of friendship.

TO KNOW YOUR ENEMY,

by blaugrana-al-vent

Chapter 1: The Way My Life Was (Childhood)

Fifteen year old Harry Potter was lying flat on his back in his bed, eyes wide open, as night came to its end, succumbing to the first sunrays of the day. He had just experienced the same nightmare that had haunted his sleep since... well always. A maniac's laughter, a cold voice, and then, green light and pain beyond anything imaginable. It was always like that. Though this dream didn't appear every night, it came back again and again, with a month's difference or a week's in between, but it always came back, as if it wanted to be remembered for all of Harry's life. When he was younger he had told his parents, James and Lily, about it, but they always gave him the same answer. 'It may be the night when your brother Karl saved us all by vanquishing You-Know-Who. We know it must have been a traumatic experience. Go back to sleep.' It was always like that. All in the Potter household revolved around Karl Potter. In fact, all in the British Wizarding Community seemed to revolve around him, the vanquisher of Lord Voldemort, the worse Dark Lord the world had suffered since Gellert Grindelwald. The 'Boy-Who-Lived', they used to call his brother, who greatly enjoyed the fame, as well as his parents, who enjoyed showing off his son and the scar he had gained in his arm in the confrontation.

Harry had asked countless times how they knew Karl had been the one to do it, but it had always been interpreted as a sign of jealousy towards his younger brother, so eventually he stopped asking. Although James and Lily obviously favoured Karl, they did not mistreat their other son in any physical way. It was all psychological. They only had eyes for Karl. The 'Boy-Who-Lived' had the bigger room; always got more food, got more presents, and more importantly he got more attention, much more than any kid should get. The few times in which one of their parents had mistaken him for his brother, who was his identical twin, were the times he had felt closer to be truly loved. This scarce occurrences were followed by an awkward moment when they realised he was Harry, just Harry, not Karl. They would usually mutter something under their breaths and walk away without talking to him.

Harry felt as he was the black sheep of the family, but he didn't even know what he had done to deserve it. Well, he did know, although it had been Karl who had triggered the situation by 'unknowingly' defeating Voldemort, and making Harry's life worse by gathering more and more of their parents' attention. Far from being dumb, Karl used cleverly every possible situation to attract more attention from anyone, and undermining Harry's attempts to be recognized by his family. It started with small and trivial situations, such as when they were still very young. Karl would start crying and throwing a temper tantrum for the slightest thing when he saw that his 'inferior than him' brother was getting too much attention. With time, the situation escalated, as did their mutual hate. Harry remembered clearly the first time when he had felt intense hatred towards him.

Flashback

The two brothers ran excitedly down the stairs towards the kitchen after they heard Lily's breakfast call. Today was their eighth birthday and they were as excited as every eight year old can be, knowing that today they would receive a large amount of presents. Well, Harry wasn't excited by that fact, as he knew he would get very little presents, compared to his brother. The fact that got Harry excited was that, finally, he was old enough to ride a proper broom. Until then he had only flown in kid's brooms, which had limited speed and altitude, and it was impossible to perform any acrobatics in them. But now, as their mother had promised two years ago, they could fly them. Harry was eager to show his parents, especially his father, how good he was on a broom. That would certainly catch his eye and make him pay more attention to him. Harry knew he was good because he had borrowed James' racing broom in the middle of the night many times. As had Karl. After seeing Harry sneak off one night into Potter Manor's grounds and fly around with James broom, he had done the same many nights. He was not amused when he found out that Harry could outfly him so easily, so he resolved to teach him a lesson.

"Happy birthday Karl!" exclaimed both parents when they entered. "And you too Harry." they added in a more bored tone.

"So where are my presents?" Karl asked.

James let out a soft chuckle and ruffled his son's hair. "Now, now, son, we have to wait for Uncle Peter and Uncle Padfoot."

"When are they coming?"

"Right now." said a voice from behind the boy. Sirius Black and Peter Pettigrew had arrived through the Floo and had made themselves at home, not even bothering to announce their arrival right away.

"Happy birthday Karl." said Peter and then added Harry in the same bored and forced voice that his parents. Sirius at least had the decency to say 'boys' and not 'Karl'. That was why Harry liked him so much. He was his godfather and no matter what, Sirius divided his attention equally between the twins, which was all that Harry could ask for.

"So can I get them now?" Karl continued.

"Let's go to the living room." said Lily giving in to her son's pleas.

Karl instantly bolted out of the room, Harry following at a slower pace. Then came Sirius, and after him Peter with both Potters. Harry saw the pile of presents beside the fireplace. He knew that most of them were Karl's and he would be lucky if he got more than just one from Sirius and another one from his parents. They started unwrapping packages. Karl opened whatever package he got his hands into, not bothering to check the nametag, as most of them seemed to be addressed to him anyway. Harry spent more time looking for his, which were scarce, and appreciating the Quidditch book Sirius had given him. Finally there was only one unopened package from the pile left. It was rectangular, about one and a half meters long, and half meter wide and deep. This had to be his new broom! Harry thought enthusiastically. He grabbed it eagerly and then he saw the name tag. Karl Potter. His previous eagerness and excitement disappeared. He sat there staring at the tag with a confused and then hurt look. He didn't even notice his brother grabbing the present from his hands. He just sat there, not moving, his gaze never leaving the space were moments ago Karl's new broom had been. After a few moments he recovered. He turned towards his brother and saw him take a new Nimbus 1900 from the box. Sirius saw how Harry looked at his brother and the Nimbus. He noticed with a sad look that no broom was to be seen beside Harry's small pile of presents, if two gifts actually formed a pile. He would be having a few words with Lily and James after that.

"But mum, where is my broom?" Harry asked glancing between her and Karl with a sad look in his eyes.

"I'm sorry dear. But brooms are very expensive, so we thought you should share with Karl."

"WHAT?" a voice echoed from the back of the room. It wasn't Harry's though, who had every right to be angry. They had told him he would get a broom, but they had broken their promise. It was Karl's voice which had boomed around the living room. He was outraged at having to share his new broom with Harry.

The raven haired boy paid him no attention as he left and run to his room, his eyes prickling as a warning that tears were coming. For once he wasn't angry at his brother. Well, yes he was, but Harry was even angrier at his parents, so Karl's rant didn't seem too important to listen to. They said that the broom was for them to share. Then why was it addressed to Karl instead of the two of them? Why had his brother gotten a broom polishing kit and a certified Nimbus wooden plaque were he could hang it? The damned broom even had Karl's name engraved in it. He dropped into his bed and started crying. This was his worst birthday ever. He should have seen it coming. Things like this usually happened to him, while his brother got anything he wanted, whenever he wanted. A soft knock in his door interrupted his sobbing.

"Go away!" he shouted. The person at the other side didn't comply and opened the door. Harry was about to shout again at the intruder but stopped himself when he saw his godfather Sirius, standing at the door. He was the person whom he loved most, and probably, the only person to love him back.

"Oh, sorry Uncle Sirius. I thought you were..." he stuttered, embarrassedly wiping away tears from his eyes though they continued to stream freely out of his eyes.

"Are you okay pup?" Harry just stared at him for a moment before turning away to hide his tears. "Okay, stupid question, sorry. Come here." he said while sitting beside Harry and pulling him into a tight hug. Harry's sobs became louder after he embraced his godfather.

"Why do they hate me so much?" he asked when he had relaxed a little.

"They don't... hate you."

"They don't love me either."

"Yes they do."

"No they don't! All they care about is Karl!"

"They also care about you, Harry."

"Stop saying that! They don't care about me. I know! They all pay attention to him only. They don't notice me most of the time!" Sirius knew all of this was true, and didn't know what to say to comfort the small child, so he just held him while the kid just took all of his frustration out. "They promised they would buy me a broom. They know how much I like flying! And then they buy Karl one. They say we will share it. But I know it's as good as his. He'll let me fly it once today probably because of what they said, but that's it. He won't allow me to ride it anymore!"

"I have an idea." Sirius said suddenly.

"What is it?" Harry asked, his voice weak.

"I always carry this with me. Seeing how much presents Karl got, and that he got a Nimbus 1900, I am giving you a second present." Then he pulled out a small stick from one of the inner pockets of his coat. He took out his wand and pronounced some strange words. Harry thought it might be Latin. Sirius handed the little stick, which was now growing steadily, to his godson. Seconds later, Harry was holding a beautiful black broom in his hands with silver decorations. It seemed old, although it appeared to be in a perfect state.

"This is my second present." Harry gasped. He was about to say something when Sirius cut him off.

"It might not be as cool as one of those Nimbus, but it's much faster."

"Which make is it?"

"None. It was custom made."

"What is custom made?"

"Custom made is when you go and ask a broom maker to make you a broom with specified speed, weight, colour, form or whatever you can think of. Big businesses like Nimbus or Cleansweep make several thousands of identical brooms and sell them. In this broom's case, there's not another one like it. It's unique. My uncle had it made for me when I was your age. I won a few Quidditch matches riding it. It is truly a magnificent broom. So as you are my 'honorary' nephew and life owes you a broom, and a good one at that, I thought it would be nice if you had it. I don't need it anymore." Harry knew he shouldn't accept it. It was Sirius' broom. It had been for... he really didn't know how many years but it was certainly a large amount of them. He sat there considering what to say until only three words come out of his mouth, or more accurately, they came from his heart.

"Thank you, Sirius!" he said, and jumped at him, embracing him. Sirius smiled and took his godson into another tight hug. He took a peek out the window while holding his grateful godson and saw Karl flying around in his new broom.

"Hey pup. How about we go outside and you fly circles around your brother?"

"Yes!" was all Harry said before grabbing his new broom and running downstairs, across the kitchen, and into the grounds.

He found his dad sitting on the stands of their own private Quidditch Pitch while looking at his beloved son. Harry observed his brother and saw that he wasn't as talented as himself. He smirked. At last, a little recognition along with a personal victory over his brother. A few seconds later arrived Sirius. Only then James seemed to pay attention to anything other than Karl. He noticed that Harry was holding Sirius' broom.

"Hey Padfoot, why does Harry have your broom?"

"It's my broom now." Harry said smiling.

"WHAT? Why are you giving him your broom. It's the only one you've had all your life!"

Sirius took James several feet away before James said anything that would hurt Harry. They spoke heatedly for a few minutes with a silencing charm around them. Harry observed them. Sirius had a murderous look in his eyes while James was arguing about something, as if he was defending himself from Sirius's accusations.

"What's that broom?" Karl sneered from his side. He had just come down and joined Harry in staring at his father and Sirius.

"It's my new broom."

"Got jealous of my new Nimbus so they had to get you an old trinket from the storage room?"

Harry just looked ahead, trying to tune out his brother's taunts. He didn't answer and just smirked. Victory was near. After what seemed hours, James and Sirius came back while Karl went to sit at the bench and started playing around with a training wand Dumbledore had gotten him for his birthday. This seemed to be the perfect moment for Harry to show his father how good he was. After receiving an encouraging smile from Sirius, he took off carefully, taking in every sensation the new broom gave him. He flied slowly a couple of laps around the pitch to get used to the new broom. When he felt more comfortable he started gaining speed. Then it happened. His broom gave a sudden, frightening lurch. For a split second, he thought he was going to fall. He gripped the broom tightly with both his hands and knees. He'd never felt anything like that. It happened again. It was as though the broom was trying to buck him off. But brooms did not suddenly decide to buck their riders off. Harry tried to fly it down and then he realized that his broom was completely out of his control. Someone had to be doing something to him, or the broom. He couldn't turn it. He couldn't direct it at all. It was zigzagging through the air, and every now and then making violent swishing movements that almost unseated him. In a short moment of peace between the violent movements, he looked down to where Sirius was, and saw his brother hiding from them while pointing his wand at him. He was jinxing Harry's broom! Slowly, but inevitably he lost height irregularly until he crashed into the stands with a sickening crunch. He felt pain erupt in his right arm. He took a look and saw he had a deep gash in his forearm, but at least he had nothing broken. Tears started streaming from his eyes as he saw that Sirius' broom had broken in many pieces.

It had all gone wrong. He was supposed to show off in front of his father and he had ended up breaking the best present of his life. And it was, again, Karl's fault. He looked up and saw Karl retreating quickly with his broom towards the house, his alibi, without doubt, and James and Sirius running towards him. He noticed his godfather first, who was following James. He was looking at Harry with genuine concern and worry. But then Harry looked at his father. He was looking at Harry with genuine anger and disappointment. What was going to happen wouldn't be nice. So he stood up, clutching tightly his right arm and took off to the Manor, running while he cried.

End Flashback

Many episodes like that had followed in the following years, and Harry learned how to avoid them for fear of his life. At the Muggle School they attended until they were ready to go to Hogwarts, Harry lived a similar situation. Karl had a wide collection of friends while Harry remained isolated. Many boys that had played with him in the playground the first days had been beaten by Karl and his little gang, so they didn't dare to come near him again.

Life at home was equally tense. The obvious difference of attention that both brothers received from their parents made Harry distance himself more and more from them. It wasn't that his parents didn't care about him, because they did, only not in the same way as Karl. They cared that he got good grades; they cared about him if he was ill or they cared about his social life when he preferred to stay in his room alone when great Karl Potter had his birthday party downstairs and many children his age where having fun. But what really annoyed Harry to the point of hating them as much as he hated his brother was that they didn't care about him when important things came up or, his brother was involved. When they had to choose between them, Karl was always the first and obvious choice. He was the first to be believed when he accused Harry of doing something he had done, he would always get better and more presents. When Harry did accidental magic, James and Lily always turned to congratulate their younger son, Karl, without even knowing who had done it. Harry felt as if he was a family pet that didn't warrant the same attention and love from his parents as their beloved son. He felt as if he was the black sheep of his family.

Slowly, after beginning to understand that the situation wasn't likely to change anytime soon, he started to distance himself from them. In this situation he turned to the only person he cared for, his godfather Sirius. The dog animagus had told him countless times that he had lived a similar situation at home when he was young, having only his uncle to turn to.

Unfortunately Sirius was no longer welcome at the Potter household. After the broom incident, Sirius had accused Karl of jinxing Harry's broom and accused Lily and James of favouring Karl while they neglected Harry. Harry remembered the argument well; he had hid behind the door and heard the row completely. Well, almost completely. He had arrived halfway through and knew that something must have been said by one of them to create such a tense atmosphere. One way or another, Harry was grateful that Sirius had come to his defence. He felt as if he was in debt with him.

The falling apart between Sirius and his parents did not stop Harry from seeing his godfather though. Usually Sirius would meet him outside school and walk him home, although they didn't always follow the most direct or fastest route back. They would always spend a couple of hours around Muggle Godric's Hollow before getting Harry home. In case his parents ever asked why he it took him so long to come back from school, he would say he had stayed back in the school's library. Had they really known him, they would have detected his lie thereupon, as Harry didn't like reading very much. Harry preferred experiencing to reading. During their daily visits to the muggle world Harry and Sirius realised how much more advanced Muggles were and they were soon fairly knowledgeable of their customs. Sirius was particularly fascinated with two Muggle inventions: vehicles and cell phones. The last few months of the last year at Muggle School before he went to Hogwarts, Sirius would come and fetch him in his brand new Harley Davidson. He had magically enhanced it and would normally take Harry flying, a thing he definitely liked.

Whenever they couldn't see each other, as in holidays or such, they would usually exchange text messages. They had come to the right conclusion that this muggle system was far more practical and efficient than owls, and thanks to magic they would be using them for free. Of course Harry kept it a secret from his family and had the cell silenced at all times. Sirius would usually send Harry many birthday and Christmas gifts every year, although he knew that James always snatched them out of Harry's hands and disposed of them, and if they were valuable sold them or gave them to Karl. Neither Sirius or his presents to Harry were welcome at Potter Manor. However, Karl always got to keep whatever Sirius had sent him.

Peter Pettigrew had chosen to stick with the Potters when he had to choose between his two long life friends after their falling apart. Pettigrew, instead of ignoring Harry much like Harry's parents and brother did, he seemed to hate Harry for some reason and was always observing him. His parents didn't notice it so Harry would never discover why he was hated by the man unless he confronted him about it.

.o0o.

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