A/N: The title in this is a reference to the 1976 film. I always felt that the movie's protagonist at least partly went off the rails due to his isolation and lack of anybody to talk to. Dark Harry.

Like Nightfall, not a nice story, but at least the world isn't going to end in this one.

My thanks to Madie080802 for her help with the monologue at the start. You rock girl!

Edit 9 June 2019: I've added a bit to the end of the story regarding why Harry didn't include Dumbledore. I also adapted the closing speech from Underworld (2003) and added it to the second last paragraph. I felt it fitted perfectly.

Edit 26 September. I added a little bit about Harry discovering the compulsion charms on Hermione.

Harry stood in the owlery, stroking the feathers of his familiar. "So, what do you think Hedwig? Everybody seems so full of themselves... I can understand Ron, but, Hermione? I guess nobody gives a flying fuck, eh? I mean, I can understand Malfoy, Snape, even that leech Skeeter, but Hermione? No-one will help me, hell no-one will talk to me. So I guess I'm a dead man walking in the tournament. And for what? For whom? I'm in a corner now. I have no choice; they are all against me. Nobody gives a fuck about me. So, I will follow their example. Like the saying goes, 'Do unto others as they would do unto you... but do it first.' Well, the-boy-who-lived is going to be The-last-man-standing."

Since his name came out of the Goblet, Harry felt everyone had abandoned him. Even Hermione wasn't speaking to him, although to be fair to her, it seemed that was mainly so she didn't get grief from the rest of the school who all, led by his supposed friend Ron Weasley, considered him a cheat. Friendless, his mind had turned inwards, and not in a healthy way. The relentless articles in the Daily Prophet had only gotten worse. He felt since no-one else would help him, he would have to help himself. He dropped out of all his classes claiming it was to train for the tournament. In fact, the tournament didn't figure in his plans at all as he didn't feel he would survive it anyway unless he got help. Once he made that decision, he investigated, with Goblin assistance, who was pushing the articles in the Daily Prophet. It didn't take long to find out who Rita was meeting with on a regular basis. It was also obvious to him who was leading the push in the castle, both among the students and the staff.

The headmaster could have done something about it, but chose not to, saying it would build character. He had likewise advised Harry that with no slander and libel laws, his hands were tied. He had conveniently failed to mention that laws protecting children were being ignored. A fact that Harry discovered when he began researching what he could do about the incessant harassment. Harry couldn't even get comfort from Fawkes while in Dumbledore's office as he had had a burning day. His godfather, Sirius Back had to leave the country; because again, the headmaster refused to help. In his role as Chief Warlock he could have ordered a trial for Sirius, even over the objections of the minister. He had also discovered lots of laws that were designed to benefit the pure-bloods.

Trips to Gringotts confirmed a number of matters for him and clarified others. Everything he was going to do was legal. Normally it was done by the pure-bloods against others, however the laws didn't say it couldn't be. Gringotts also allowed him access to the Potter heirloom vault. A goblin accompanied him and was able to explain the significance of certain items found there, two of which he removed and took with him back to Hogwarts.

Nobody who knew him appreciated how much Harry took after his mother. The epithet 'brilliant but scary' was applied to Lily long before Hermione came to Hogwarts. Unlike Hermione, Lily wasn't worried about hurting people who she felt deserved it. Harry was extremely observant, and now turned inwards with no-one to correct the path of his thoughts, he observed and plotted.

Professor McGonagall had noticed how withdrawn Harry was becoming and had spoken to the headmaster, pointing out that aside from being asked something in class, Harry had not spoken a word in the castle in several weeks. Dumbledore had forbidden her from interfering. He didn't share this with his deputy, but he wanted Harry isolated so that when the time came, he would sacrifice himself for the greater good. He had to use compulsion charms cast by the Elder wand to prevent Miss Granger from staying with him. He had to re-apply them every couple of days even using the Elder wand.

Harry went to Gringotts on a Friday afternoon and performed a small ceremony with a large effect. He left there and walked to the magical records office, arriving at 4:59. Having bought some Polyjuice potion in Knockturn Alley and Accio'd some hairs from a muggle barber shop earlier, he had entered the ministry as himself and then taken the Polyjuice in a toilet, walking out as a young muggle adult. He observed the clerk putting on her cloak as he approached the window. Apologetically, he said. "Sorry to be so late, just got some things that needs to be filed."

"Nae bother," said the Scottish lady as she deftly stamped the documents and put them in the 'To Be Filed' tray without even reading them, which was a pity in many ways. Harry thanked her and she nodded, not noticing the cold smile on his face. With that, she shut the window and walked out the door. She wouldn't return until Monday morning.

He then left and went into muggle London and caught the knight bus to Little Whinging. Knowing no-one would be home at that time on a Friday, he went to the garden shed under his cloak and grabbed a container there before returning to London. He made it just before the Polyjuice wore off.

Harry returned to the castle via one of the tunnels with no-one the wiser. Since he was a tournament champion, he was excused from classes. After another silent meal alone with his thoughts, he went up one floor and made a detour before returning to the tower and tried, and yet again failed, to fall asleep.

The following morning was the weighing of the wands ceremony. After another silently lonely meal, Harry went up to the appropriate room.

Despite the vicious articles she had published, Harry agreed to be interviewed by Rita. As she led him towards the other side of the room, Harry stopped her. "Excuse me, you have an insect in your hair, let me get it out." Harry put his hand in her hair and pretended to remove the beetle that actually came from his pocket. No-one noticed the very fine powder that he poured into her hair and onto her scalp. The chemical was soon being absorbed through her skin. After they finished the interview, Harry suggested she may want to stay around outside the great hall over lunch as he suspected something newsworthy was going to happen. Skeeter nodded, intrigued.

The weighing of the wands ceremony proceeded quite normally for such things. Harry was not in the slightest bit concerned about the event. His mind was on lunch.

Harry had observed that when he visited the castle for whatever reason, Lucius Malfoy stayed for a meal with his son and Severus Snape at a separate table. This table was immediately in front of a little used entrance to the great hall that was kept locked. Harry had come through the night before and oiled the mechanism as well as casting silencing charms over the entire door. They would only last a day, but that was long enough.

Coming up to the door under his invisibility cloak, Harry opened it slightly and squeezed through. He had cast silencing charms on himself as well. Coming up behind the three seated figures, he heard Draco say "I wonder where scar-head is? He's been sitting staring at me at most meals."

"Probably finally recognized you as his better." Sneered Severus.

"Don't worry Draco, the articles I'm having Rita write will make sure he continues to be alone." Said his father.

Harry held the two Goblin forged daggers with their basilisk venom coated blades horizontally behind Lucius Malfoy and Severus Snape. He carefully positioned both blades just to the left of their spine about at the bottom of their shoulder blades. Taking a deep breath, he shoved both razor-sharp blades forward. The left briefly scraped on a rib before both plunged forward into the men's hearts. The movements of the beating hearts caused them to further damage themselves on the blades. Releasing the daggers, he flicked his wrist and his wand dropped into his hand from his father's Auror-grade wand holster. Pointing his wand at Draco's neck at the base of his skull, he muttered "Reducto!". At a range of three feet, he couldn't miss. There was a small thump as bone fragments from the skull were driven into the brain stem and cerebellum. Draco's head dropped forward into his food. He was already dead.

Severus and Lucius were not dead yet, but the pain from the wounds and the basilisk venom paralyzed them both. Their ruined hearts tried to keep beating for a few seconds and carried the venom to their brains. Lucius had a few moments of lucidity to see his dead son before losing consciousness. 5 seconds later he was dead. Severus also saw his dead godson before succumbing.

Harry carefully removed the daggers from the bodies and cleaned them before sheathing them on his belt.

A few seconds past as Harry, having removed his cloak, just stood there having completed his task. Pansy Parkinson turned and looked over her shoulder at her at her betrothed. Seeing his head where it was, she stood and walked over, confused. Harry stood quietly and watched her as she stared uncomprehending at the scene before her brain finally interpreted what she was seeing. Then, horror filling her eyes, she started screaming before collapsing sobbing on the floor.

Hearing the noise, a certain reporter changed into a water beetle and flew into the room.

Harry just stood there as, led by Madam Pomfrey, the staff rushed over. She quickly cast diagnostics on Severus and Lucius. With one glance, she knew there was no point with Draco. Turning to the headmaster, she shook her head before conjuring sheets over the three bodies.

Dumbledore looked at Harry in horror. "Harry, what have you done?"

Harry just ignored him so Dumbledore almost shouted "Harry!"

Harry just looked at the headmaster with no expression on his face. "Are you talking to me? I suppose you must be, I'm the only Harry here."

"Harry, what have you done?" Dumbledore repeated, his voice just above a whisper.

"What I had to." Harry said, his voice completely flat and devoid of emotion and yet curiously child-like. "They wouldn't stop you see. They just kept attacking me. I had to make them stop, I had to. But I knew they wouldn't listen; I knew they wouldn't stop. They were just like my aunt and uncle, the ones you keep sending me back to. They're only interested in hurting me, hurting my mind and hurting my body. Kicking me, beating me, calling me names. Names like cheater and freak. It's all their fault, it's all of you people's fault." He said looking around. He laughed mirthlessly, "Tell me, is it paranoia if everyone really is out to get you?"

"Everyone was doing it you see? You made sure no-one would help me, not even my so-called friends. So, I had to do it myself you see." At that comment, Hermione broke down and sank to the floor sobbing. Harry glanced at her curiously then continued in a completely matter of fact voice. "They were the ring-leaders and I knew if I stopped them, everyone else would stop too."

Harry turned to the completely silent student body. "See, no-one is trying to hurt me now."

Dumbledore stood in shock, pale, trembling and sweating. 'How could this have happened? I knew he was isolated as I planned, but this? How could he possible think this was a solution? Anybody else would have…' Here the Headmasters thoughts stopped. He had completely isolated Harry, he didn't have anyone to tell him what he was doing was wrong. No-one to be the voice of reason as his own reason slipped away. As the unthinkable became thinkable and then the only solution.

Dumbledore shuddered as a chill ran up his spine. Now, there was nothing he could do, the Malfoy line was ended as was the Prince line. His weapon was going to Azkaban.

"Harry, I must call the Aurors. I can't see you avoiding prison." Dumbledore said quietly as Professor McGonagall and a lot of students silently wept.

"Oh no headmaster, it's all legal." Said Harry in the same flat emotionless child-like voice. "I found out a lot of what you've been keeping from me." He held up his hand and a ring appeared, "I'm now head of House Potter."

"Harry, even being head of house won't stop you going to trial."

"I know that Professor, but a declared blood feud will. I declared feud against 3 houses yesterday."

The headmaster's blood ran cold. "Three?" He asked.

"Yes." Replied Harry before seemingly going off at a tangent. "Did you know that an Animagus takes on all the physical traits of their form, including their biochemistry?"

Dumbledore frowned, not understanding the term, as Harry looked as his watch. "Soon, I think." Harry said.

In the silence of the hall, a few seconds later a high pitched buzzing was heard as a water-beetle dropped to the floor. The buzzing raised in pitch before it suddenly stopped and the beetle grew to reveal the form of Rita Skeeter. Madam Pomfrey raced over, waved her wand, shook her head again then conjured another sheet.

Dumbledore, again horrified, whispered, "how?"

"Oh, that was easy, I went to my uncle's shed and got an old shaker of Dieldrin insecticide dust. I put some on her skin where it was absorbed. Once she changed to her beetle form, the Dieldrin killed her. I knew she wouldn't stop writing articles about me, even if Mr Malfoy wasn't paying her anymore."

Harry turned to the headmaster. "Why do you hate me so much and pretend to be my friend? You wouldn't do anything to stop any of them, even though it was in your power. So, I stopped them myself. I had to make them stop."

A thought chilled Dumbledore. "Are you sure it's only 3 families you declared feud against?" Asked the Headmaster.

Harry realized immediately what the headmaster was actually asking. He answered lightly as if he had not a care in the world. "Oh yes Headmaster. Even though you are my enemy too, declaring feud against you would be illegal as you are head of the Wizengamot, But I can wait." Dumbledore paled even further. Harry paused, "I think I'll go and have a nap now." He turned and walked towards the doors of the great hall, the students parting before him in complete silence.

Pausing before the still sobbing Hermione, he looked down at her puzzled. "Why are you crying? You chose to ignore me." He then cast a charm and studied the results. "Ah, compulsion charms by the headmaster, that would explain it." He looked contrite. "Sorry I grouped you in with everyone else." With that, Hermione's head snapped up. She stood and stared at Harry briefly before she turned to Dumbledore with a look of murderous rage on her face. She started to draw her wand, only to have it snatched from her hand by George Weasley as Fred held her arms. "Uh uh Hermione, killing him would only be a momentary pleasure and it would be bound to get you talked about. Besides, charms like that are illegal, let the DMLE handle it." Harry ignored this byplay and exited the great hall.

Dumbledore looked at Hermione briefly before staring at the door where Harry had left through. He knew that even though what Harry had done may have been legal, that wouldn't stop elements in the Wizengamot acting. Though he could not predict the future, the consequences of this day would reverberate through the halls of power for many years to come. A head of an ancient and noble house was dead and three lines ended, all by Harry's hand. Soon, the Wizengamot would meet, and a tide of anger and retribution would spill out into the night. Differences would be set aside, alliances would be made and soon, Harry would become the hunted.

Dumbledore sank to the floor thinking, 'what have I done?'

A/N This is a one-shot, it's now complete. I have no intention of writing any more for it. Please review, it's my only payment. Trolls will not be fed.