Chapter – 1- The Legend of the Dark Knight
I don't own The Dark Knight Trilogy or The Harry Potter books, the plot is only mine. The two are owned by their respective creators.
It was a morning of silence, caused by the recent events in the Wizarding World. Harry was looking out his window as he saw the Dursleys leave the house. Harry was recounting the events. The fact that Dumbledore was dead and now Voldemort was at large. Harry knew that the Horcruxs were the things keeping him alive. He knew that by destroying all of them, Voldemort would be finished once and for all. He thought he would set off on his mission after Fleur and Bill's wedding. He then got up and apperated to the Burrow. He didn't know that a "Dark Knight" would step into this war.
In City Hall, Gotham
Batman Day 7:05 pm
All the people of Gotham gathered outside City Hall to celebrate the first "Batman Day." Commissioner Gordon delivered a speech telling the efforts of Batman and with which a law was passed called the "Dark Knight Law" that has helped the police capture many criminals. "And if people still don't know who their hero, their saviour, their knight. It was the Batman, the commissioner said as he exited the stage and lighted the Bat Signal to remember him. But deep down, he knew who the hero was behind the mask.
Beneath Wayne Orphanage

Bruce, who had survived the blast, was in the cave, which now was his home.
He was sitting next to his monitors and an old, dusty box of his father's letters. He was eating a sandwich he had made for himself. He thought that, at last, Gotham didn't need the Batman, and he could live his perfect life. Selina came in wearing a black dress. "What's on your mind, Bruce?" Selina said. "Nothing, just this box of letters my dad sent to some wizard or something. His name is James Potter." Selina was standing with her eyes wide open and round as saucers, she said, "Wait! James Potter? As in Harry Potter's father?" "Who?" Bruce asked as he questioned how she had known that fact. "Wait, you know something about him, don't you?" Bruce said as he wanted to know more about this "Harry Potter". Selina then broke into an explanation about the Wizarding World and the threats and everything. Bruce was shocked at the state of the world of wizardry that had the same problems as Gotham: Corruption, Criminals, and Even Discrimination. He then also learned about the war that had ignited and Voldemort's rise and Harry's ventures, and his survival of The Killing Curse, and he realized that he and Harry were the same. They both had lost their family at a young age. "Selina", he said, "If they need an ally, who's going to help?" "No one", said Selina "No one's going to help as many fear of Moldywort whatever killing them and the ones who are fighting against him are few as he has a whole army to himself and he is picking his enemies one by one." Bruce then picked up a letter from the box that was the latest. It read, "My dear friend, I am in Gotham safe and sound with my family. I hope Voldemort has not gotten to you. Remember, don't lose hope, and if he gets to you, remember, many are there on your side, and if he comes back, my son will step up like I had." Bruce got up and walked to a cabinet with his suit and arsenal. "Bruce, you are not thinking what I am thinking you are thinking!" said Selina as he looked at the symbol he was. "Selina" he said, "This symbol, this was a result of my parent's death. This symbol gives peace, hope, and light. Gotham has the light, and now this other world needs that. My father would have done this if he was in my place." Selina said. "Fine, I will also help since you always believe in good like me, but Voldemort is powerful and has a whole army of followers. How will you fight it? Bruce said, "Simple, I will fight like I always have and always will." Then, Bruce reached out for his cowl, saying, "It's time to come back from sleep, buddy."
In the Burrow
Before the Wedding
The Burrow was quiet after the emotional weight of Dumbledore's will. Harry, Ron, and Hermione sat on the worn couch in the living room, their thoughts heavy as they processed the day's events. Harry was thinking about the Horcruxes, Ron fiddled absentmindedly with the lining of his robes, and Hermione clutched a muggle newspaper tightly in her hands.

After a long silence, Hermione finally spoke. "There's something I think you need to hear," she said, her tone deliberate but filled with urgency.

Harry glanced at her. "What is it?"

Hermione unfolded the newspaper, turning to an article on one of the inner pages. She held it out to show them, pointing to the headline: Batman Day Celebrated in Gotham. Beneath it was an image of a glowing Bat-Signal, projected into the night sky over Gotham City's towering skyline.

"Batman?" Ron repeated, frowning. "What kind of name is that?"

Hermione ignored his skepticism and leaned forward. "Listen. Batman was... is... a legend in the muggle world. He's not like anyone we've ever known. No one knows his real name or identity, but Gotham celebrates him every year on this day. He hasn't been seen in years. They think he's gone."

Harry tilted his head. "Gone? Dead?"

Hermione hesitated before answering. "Maybe. But here's what's important. Batman wasn't magical, but he became a symbol—something bigger than just a man. Gotham was a city drowning in crime and fear, and he dedicated himself to fighting it. He wasn't ordinary, Harry. He was brilliant, fearless, and relentless. He made people believe they could fight back, even when it seemed impossible."

"How did he do it?" Harry asked, intrigued.

Hermione shook her head. "That's part of the mystery. No one knows exactly how he did what he did. He used technology—gadgets and vehicles—and somehow, he learned how to be the perfect fighter and strategist. People say he prepared for years, but where and how... that's something no one's ever figured out."

"What kind of villains did he fight?" Harry pressed, leaning forward in interest.

Hermione took a deep breath, her gaze steady as she began. "There were so many, but I'll tell you about the worst. Ra's al Ghul—the leader of the League of Shadows. He believed cities like Gotham were irredeemable and wanted to destroy them to 'restore balance.' Batman stopped him—barely."

"Then there was the Joker," Hermione continued, her voice dropping lower. "He wasn't just a criminal—he was chaos itself. He thrived on destruction, wanted to prove that everyone was as twisted as he was. He forced Batman to make impossible choices, and his reign of terror was unlike anything Gotham had ever seen."

Harry frowned. "Did Batman stop him?"

Hermione nodded solemnly. "But not without cost. The Joker destroyed Harvey Dent—Gotham's district attorney, its beacon of hope. He turned him into Two-Face, a man obsessed with chance, flipping a coin to decide who lived and who died. Batman took the blame for Dent's crimes so that Gotham could still believe in him."

Ron furrowed his brow. "Why would he do that? Why take the blame?"

Hermione's tone softened. "Because Gotham needed hope. Batman believed the people needed to feel they could win, even if it meant sacrificing his reputation."

Her expression darkened as she continued. "But then there was Bane. A mercenary. He broke Batman—literally. He broke his back and left him for dead, while he tried to destroy Gotham with a nuclear bomb. But Batman came back. He fought through the pain, defeated Bane, and saved the city."

Her voice faltered, and she looked down at the newspaper. "He sacrificed himself. He flew the bomb out over the bay, where it exploded. That was the last anyone saw of him. Gotham believes he's dead."

Harry stared at the photograph of the Bat-Signal, captivated. "And you don't think he is?"

Hermione hesitated. "I don't know. He was unlike any muggle I've ever read about. If anyone could survive something like that... it would be him."

Ron leaned back in his seat, skeptical. "Okay, but what's he got to do with us?"

Hermione lifted her eyes, her expression resolute. "Batman fought against fear and chaos—he thrived in the shadows and never gave up, no matter how impossible the odds. If he's still out there, he could be an ally. And if he isn't... maybe the symbol of what he stood for can still inspire us."

Harry sat back, lost in thought. Hermione's words hung in the air, the idea of a muggle standing against darkness stirring something deep within him.
Next Chapter: The Dark Knight's Message