This is the story of an phsycopath Harry Potter. Unlike a lot of those stories this on is in forth year when Harry gets caught butchering cedric diggory. This is just a one shot.
Before: (just a summary) before he joined hogwarts he was always weird people stayed clear of him because he was a problem child. The wizards like albus dumbledore believed that it was his magic that made him different, but only his aunt knew the truth when she saw five years old Harry carving a cat with a blank face and curious eyes.
Harry stared at the dead cat with curiosity and thought, where did he go? Why did stop that noise. The noise was annoying anyway, but the red water was exciting. He never understood those useless humans. Those weird annoying emotions. They genuinely cared. Why? He had to stand in front of the mirror and practice those emotions yet the humans actually felt it. Humans were weird, but why was no one like him. Someone who understood him. Stupid, weak, pathetic humans. Hmm the red liquid stopped he snapped his fingers holding it in midair watching the last of the red liquid coming out, smirking at the horrified aunt tuny, honestly why did she care about a tabby? Hmm humans.
Harry learned very quickly that all he had to do was show aunt petunia a little blood and she did what he needed of her. He could act like other children, be the sweet misunderstood little Harry. People adored him, he could make sure they see only what he wanted them to see. He only showed his true colours at home, his home. The only thing he cared about was his strange powers, magic they made him feel warm like blood.
So when the giant buffoon came to his house he saw that perhaps this new world were like him. Unfortunately on the first meeting with the man he understood that even in this new world he was special, but perhaps just perhaps there was someone else like him, what was the name, yes, lord voldemort. There were other concerns but this boy who lived, he just had to show people what they wanted to see.
End of first year: He stood in front of the mirror as the stone dropped in his pocket, he inclined his head and the ropes disappeared. He turned around to look at the dark lord in the blood red eyes.
"Harry Potter, give me the stone"
How stupid was this man, if he didn't want to give it to him then he wouldn't be here. "Yes, yes lord Voldemort, I was coming to that, do you cause people pain, like what you did to neville's parents, how does that work".
"What are you talking about boy"
"I was saying that I will give you the stone, but I want something in return, I want to help you, cause pain. I mean you do not have these weird feelings do you I never understand these humans. You are not human are you?" Harry was genuinely confused and saw surprise on the white face.
"You are saying that you are a phsyco, and you want to work with me"
"Accurately put, yes but I do not bow to anyone"
"That can be arranged, you would have to spy for me it would be like a partnership so both of us will give a vow not to willingly hurt each other"
"That would be fine"
"Welcome to the dark side"
Harry was genuinely curious.
Forth year: Harry was going to reveal himself, since it was obvious to voldemort that he could not stay at the light side without killing them all, so since after three years voldemort had revealed himself, so was Harry going to as there were more useful spies since Harry had a piece of Voldemort's soul.
Harry was sitting on a chair not even tied by ropes, idiots no idea what he was capable of. The tortured body of cedric diggory was laying there, it truly was a masterpiece. Once all the horrified professors, his friends and dogfather were inside the headmaster's office, and the body was gone. Dumbledore spoke in a grave voice, "who did it? was it lord Voldemort, is he back my boy".
"Unfortunately not headmaster, he didn't even play with me, Bella was the only one who helped me, he just gave me orders and then left, rude"
"Did he torture you, Harry are you alright" Sirius spoke turning into human again.
"Aren't you listening at all, no he didn't torture me and I doubt he can, why did you ask that? It's not like you care about me, you left me as a child for revenge so revenge is more important. I mean you left me with petunia and her husband, they abused even tortured me but it's not like you cared you never bothered, you leave me whenever you want and anyway to you I am James's son not Harry."
"Of course I care about you, Harry you are my godson, wait the Dursleys abused you?"
"Yes beat me, even tried to rape me but I got my revenge, though the only thing that kept me sane in hogwarts were the house elves"
Finally granger could not stay quiet, "how could you do that Harry they are innocent elves, this is slavery and cedric they did nothing to you, what happened to you?" Granger sobbed at the end.
"No, but what are you crying for, cedric was nothing to you, you weren't even friends and the house elves are a different species".
Barty, standing polyjuiced as moody was standing at the back and smirked at him. Everyone was left speechless with the question and Dumbledore in his infinite wisdom explained to him. "My dear boy cedric was a good boy and he is going to be missed by the entire hogwarts, but the loss to his parents is unimaginable". Harry was not at all impressed.
"That maybe but you cannot cry about the death of an muggle boy in Pennsylvania, or is this the strange emotion called empathy, hmm humans are weird". Humans were so stupid, but why did they cry about the death of the boy who was gone and they never even knew him.
"This is going nowhere potter, you are going to tell me if the dark lord is back, did you beat him" Snape snarled. Harry thought about rolling his eyes, why was this idiot asking him that, he had the dark mark.
"He is your master, why are you asking me that?"
"What makes you think I am a death eater potter? And where did you hear that?"
"Please anyone with half a brain can tell you that". How stupid were they? "Anyway since you miss him so much you will see him in a few minutes, you can't even resist because you see the dark mark is a very ingenious piece of magic. When you resist the dark lord it first starts to burn then turns your veins black, it is like burning acid inside your veins it is agony then the acid slowly goes to your heart and infect it, it is an ingenious piece of magic". Harry loved messing with the man, but he had to find out where his loyalty laid.
Snape was so pale it would put the ghosts to shame, "how can you possibly know something like that?"
"Tch tch, now that would be telling wouldn't it professor" Harry smiled maniacally. "How about we play a game an answer for an answer snape".
"Now first question is why do you hate me?"
"What are you doing potter?" On the corner of his eyes he saw Dumbledore nodding and Barty smirking, this was just a play for time.
"Playing a game, your answer professor?"
"Because I loath your father, and you are just like him", such an arrogant man who didn't even knew him yet made baseless assumptions.
"My question, who killed cedric diggory?"
"Bellatrix lestrange, my turn where did you know petunia", it was true she gave the blow that took his life.
"I knew her when I was younger than hogwarts age, she was your mother's sister". Curious very interesting, "my turn what did the dark lord do to you"
"Nothing, it was all bellatrix" he wasn't going to make this easy. "Last question what did you say to the dark lord after telling him the prophecy".
Severus once again became pale, "I told him to spare your mother" Harry already knew that but it meant that Severus's loyalty was to his mother. "What do you know of the prophecy?"
"That it is a fake" this time Dumbledore became pale.
Barty signalled him that the mission was done and Harry stood up. He smiled softly at Dumbledore then threw a severing charm at Dumbledore breaking his wand arm and filling the office with blood. Everyone had gone still in shock and Dumbledore's eyes had widened in surprise and agony. He smiled the sweetest smile and walked up to Dumbledore, trying to stay upright and narrowed his eyes he wanted to see him on his knees. He cast another severing curse, causing his other arm to go flying across the room. Snape moved forward to stop him but moody or Barty came from behind, took his wand and chained him with indestructible chains.
Harry cast a full body bind on sirius, ron and hermione. Than he he looked back at Dumbledore, casting another cutting charm and taking of his beard with a bit of the skin from his chin. Dumbledore was doubled over in pain and trying to reach his magic. Harry sighed happily and then cast the cruciatus in parsletounge, triple the pain of the normal one. Dumbledore fell on his knees and let out an whimper, his bloody stumps shaking, unfortunately he had to finish this so he would not bleed out.
Barty's eyes were wide and obviously enjoying it. The rest had tears in tears in there eyes and horrified expressions. He looked back at the whimpering Dumbledore, aimed at his stomach and smiled softly like a child with a new toy.
"Goodbye Albus Dumbledore and I will ensure that the world remembers you as a fool and lying, manipulating bastard".
Then he pointed his wand at Dumbledore's stomach and spoke the wrinkle smoothing charm. The charm straightened his intestines, Dumbledore let out another whimper then a scream, falling down on a pool of his own blood.
He exchanged smirks with Barty, the dark had won, Dumbledore was dead.