The Fifth Marauder

The bus stop was a cacophony of city noise—honking horns, chattering pedestrians, the energetic 'hustle and bustle' one could only expect from a place like London. William Keating adjusted the strap of his messenger bag, his mind still spinning following his advanced calculus course that morning. Calculus had always been more than just numbers to him; they were elegant puzzles waiting to be solved, and advanced calculus was his foray into the world of mathematical logic.

Cringe, he thought, forcing his mind to a stop. He knew his passion for mathematics was not one shared by many. "Seriously," he muttered to himself, "Professor Hartley's proof for the limit of that integral was brilliant." A smile tugged at the corner of his mouth. Most of his classmates would have glazed over, but William lived for these mathematical moments—the pure, crystalline logic that transformed abstract symbols into universal truths.

His phone buzzed. Jake.

"Dude, you want to grab coffee?" his best friend's message read.

William typed back quickly. "Can't. Need to prep for tomorrow's exam. Raincheck?"

Jake's response was immediate. "Nerd. I think not, bruv. Meet me at Lucky's in an hour."

A laugh escaped William's lips. Fair assessment, he supposed. Mathematics was his sanctuary, a world where everything made sense—unlike the messy, unpredictable landscape of human relationships. He wasn't shocked by Jake's assertiveness—Jake was always like that with him. Even though William grew up with three brothers, Jake was the only person who knew how to handle his antisocial tendencies and force him to go out.

The truth was, Jake was his only real friend—and even that was a stretch. Growing up, William had been that kid: the one teachers called "gifted," parents bragged about, peers resented. Skipping grades, winning math competitions, entering grad school before most of his high school classmates had chosen a major. Brilliant, they'd all said. Prodigy, they'd whispered.

But brilliance was a lonely road.

His brothers—all three of them—had followed more traditional paths. Sports, business, engineering. They loved him, sure, but never quite understood him. Family gatherings were a minefield of well-meaning but awkward conversations. "So, William, still doing... math things?"

Books had been his true companions. Not just textbooks—though those were his first love—but worlds of fantasy and imagination. Percy Jackson had been a particular favorite, a escape from the constant pressure of being the "smart one." He'd read the series so many times the pages were soft and worn, the spine cracked from countless readings. In those magical pages, being different wasn't a burden. It was a gift.

Today felt different, though. Something light bubbled in his chest—an unfamiliar sensation of pure, uncomplicated joy. The exam tomorrow didn't feel like pressure. It felt like an opportunity. The mathematics department at Imperial promised that if—when—William performs well on this exam, he would be allowed to join the Calculus Research department at Imperial as a paid researcher. Jake had plans to celebrate afterward, promising to drag William away from his books and into the real world. For the first time in years, William was looking forward to something beyond equations and theorems.

He felt... happy. Truly, genuinely happy.

The light changed. Pedestrians surged forward.

William stepped off the curb.

He never saw the bus.

The impact was instantaneous—a thunderclap of metal, a spray of glass, a crushing weight that obliterated thought. One moment he was calculating derivatives in his head, the next... nothing.

Just darkness.

And then, inexplicably, light.

***

When William's eyes opened, everything felt wrong. Smaller. Unfamiliar. The ceiling above him was a pale, creamy white, decorated with an unhealthy amount of blue paint and rocket ship decals. His body—his hands—were tiny. Child-sized.

What the actual hell?

Memory crashed into him like a wave. The bus. The street. Death. But this wasn't the aftermath he'd expected. This was... something else entirely.

A woman's voice drifted in from another room. "William! Breakfast is ready!"

Not his mother's voice. Not his home. Not his life.

William Keating, 21-year-old mathematics graduate student, had apparently become 10-year-old William Keating—inhabiting an entirely different body, in an entirely different life.

The universe, it seemed, had one hell of a sense of humor.

***

The room swam into focus—soft yellow wallpaper with faded rocket ship decals, sunlight filtering through curtains that felt somehow... different. Older. Unfamiliar. William's hands—no, this body's hands—were tiny, pale, slightly chubby with the roundness of a child just on the cusp of pre-adolescence.

Something classical played softly in the background. Not from a smartphone or digital speaker, but from an actual record player, its warm crackling sound creating a strange, distant atmosphere.

"William!" The voice came again. "Breakfast!"

His brain struggled to process. Everything felt wrong. The textures. The sounds. The light. This wasn't his bedroom. These weren't his hands. This wasn't his life.

Footsteps approached. A woman—his mother, he supposed—entered the room. She wore a pale blue dress with a white apron, her hair in a precise style that looked carefully maintained. Something about her outfit seemed... dated. But he couldn't pinpoint exactly how.

"Come on, sleepyhead," she said, her tone warm but brooking no argument. "Your brothers are already getting dressed. Thomas! Michael! Robert!"

William froze. Those names. The exact same names as his brothers from his previous life.

What were the odds?

He managed a mumbled response that was more grunt than words. His mind was a whirlwind of confusion, trying to make sense of this impossible scenario.

The woman—Mom?—didn't seem to notice his internal turmoil. She straightened his collar, brushed some invisible lint from his pajama top. So domestic. So... different.

He quickly got dressed with the clothes conveniently already laying on his bedside table. The shirt was soft from multiple washings, its collar slightly frayed, and a barely visible patch near the bottom suggested a recent repair. His shorts were a faded khaki, pressed but not crisp—ironed with care, but not perfection.

Following his mom in what he could only describe as instinctual, he stared in awe at the family photographs in mismatched frames set along the wall. A narrow side table held ceramic figurines and scattered mail, the wooden floors creaking softly with each step. William's mind categorized all of this information as it did in mathematics, but internally, it felt like his head was splitting in two.

"Sit. Eat your eggs before they get cold," she instructed, completely unaware of her son's mental breakdown.

From another room, boisterous boy sounds erupted. Laughter. An argument about something trivial. Sounds of siblings, of a morning in a family that felt simultaneously familiar and alien.

William stared at his plate. Scrambled eggs. Toast. Orange juice in a glass with a chip on its rim. Perfectly ordinary. Perfectly strange.

"How improbable," he muttered to himself, the academic part of his brain trying to regain some control.

His mother raised an eyebrow. "What was that, dear?"

"Nothing," William responded automatically, his mind racing but his body moving on autopilot.

Thomas, lanky and sun-browned from summer, leaned across the table. "You gonna eat those eggs or what?"

The twins, Michael and Robert, were locked in a silent war over the last piece of toast. They looked identical, down to the cowlicks that refused to lay flat and the spattering of freckles across their noses.

Their mother bustled around the kitchen, packing lunches in brown paper bags. The radio crackled with a news report, then switched to a chirpy summer song. Outside, the July heat was already building, promising another languid day of childhood freedom.

The next 30 minutes passed uneventfully for William, and he was internally grateful that none of his siblings or parents tried to force him into conversation. William watched silently, waiting for his headache to abate, but it refused.

"Don't forget to keep an eye on William," she called to Thomas as she prepared to head out to work, who rolled his eyes. At 14, it seemed like he defaulted as their caretaker, although to William, he just looked like the oldest of four boys trying to navigate a summer day without their parents.

William watched, fascinated. These weren't just names copied from his previous life—these were living, breathing people. Each movement, each interaction felt both alien and strangely familiar.

Their mother interrupted the breakfast chaos, pulling a peculiar envelope from her apron pocket. "William, this came for you this morning. The strangest thing—it came right through the window. I don't know which of your friends sent it, but make sure to let them know that while your father and I may not be home often, we will not allow this absurdity. We have a mailbox for a reason"

William nodded, a bit shocked at their mother's 'no-nonsense' tone. She reminded him a lot of his own mother. His real mother.

The envelope was heavy, made of thick, quality parchment that seemed out of place in their modest kitchen, with a defined red 'H' stamped over it. William's mathematical brain immediately began cataloging its unusual characteristics—the color, the weight, the peculiar way the address was written.

Thomas leaned over, curious. "What's that?"

William's hands—small, child-sized—felt almost disconnected as he carefully broke the seal. The twins stopped their squabbling, momentarily distracted.

He unfolded the letter, reading:

"Dear Mr. Keating,

We are pleased to inform you that you have been accepted at Hogwarts School of Witchcraft and Wizardry..."

The words blurred. Something fundamental shifted in the universe.

Accepted. Hogwarts. Witchcraft. Wizardry.

His previous life's obsessive reading of fantasy novels chose that exact moment to short-circuit his brain.

"Shit." William heard himself say, with the profound understatement of someone whose entire reality had just been turned inside out. He hadn't yet processed his new situation, but his mind was no stranger to jumping to conclusions. This new life of his, it seemed, was about to get very complicated.

**

Thomas, Michael, and Robert immediately burst into laughter, the sound echoing through the small kitchen. "Dude, which of your friends sent you that crazy letter?" Michael asked, chuckling. "Hogwarts School of Witchcraft and Wizardry? Come on, Will!"

William's face burned as he stared at the letter, his mind reeling. They didn't understand. This wasn't a prank. This was real.

And that meant… Voldemort was real. The Dark Lord, the one who had killed so many wizards and witches. William's heart skipped a beat as he thought about it. He was going to be a part of this world, a world where magic was real and so were the dangers that came with it. Better yet, from the reactions of his brothers, he was muggleborn. 

William cursed, internally. He figured that if he was going to be reborn into the Harry Potter universe, whatever wicked God had sent him there should have at least let him be born from a powerful family like the Potters. Hell, even the Weasleys would be better than being a muggleborn in this era!

The laughter and teasing continued, but William tuned it out, his thoughts consumed by fear and uncertainty. What if he wasn't good enough? What if he got hurt? What if…

Michael's voice cut through his thoughts. "Hey, Will, you okay? You look kinda pale."

William forced a laugh, trying to play it cool. "Yeah, I'm fine. Just...just a weird prank, I guess."

But Michael's expression was skeptical. "You sure? You seem really freaked out."

William hesitated, unsure of how to respond. But before he could say anything, Thomas, his eldest brother, spoke up.

"Hey, Will, you want to come with me to the shop? I need to pick up some stuff for my bike."

William nodded, grateful for the distraction. "Yeah, sure. I'll come with you."

Thomas's long strides forced William to take two steps for every one of his brother's as they walked down Palmer Street. William was still getting used to his lanky body. Even in his first life, William could not be considered tall—a respectable 5'9'', but nothing compared to his brothers, who were all well over 6 feet tall. Still, it was hard adjusting to his new 11-year-old body, as he was now lanky and only as tall as his older brother's stomach.

The summer heat rippled off the pavement, but Thomas seemed unfazed, nodding to various people they passed. A group of older teens waved from the corner store's steps. "Tommy! Haven't seen you 'round lately," one called out.

"Been busy with the kids," Thomas replied, ruffling William's hair.

William ducked away from the gesture, noting how his brother seemed to command respect despite his age. The observation struck him as peculiar - in his previous life, he'd never known fourteen-year-olds to carry themselves with such authority, but it made sense from his observations at breakfast. 

"What'chu doin' today?" the tallest of the group asked, a cigarette dangling from the corner of his mouth.

Thomas shifted, one hand still resting on William's shoulder. "Just takin' this one out," he jerked his thumb toward William. "Needed to get out of the house, didn't we?" He gave William a quick wink.

"Gonna be about later?" another boy called out. "Might head down the pub—er, I mean," he caught himself, glancing at William, "might hang round the corner shop."

Thomas nodded, a knowing look passing between them. "Depends when Mum and Dad get back from work. You know how it is." The phrase carried a weight of understanding—a shared experience of working-class kids suddenly thrust into quasi-adult responsibilities.

The boys exchanged a series of nods that seemed to communicate entire conversations. William watched, fascinated by the unspoken language of teenage boys in this era.

"Might swing by if I can," Thomas said, his tone casual but deliberate. "Gotta keep an eye on the lot."

If William had to guess, Thomas was the responsible one in the family. He wasn't surprised, considering how quick his parents had been to ask him to take care of all three of his younger siblings that morning. It was a heavy burden for a teenager to bear, but from what William could see, Thomas handled it with a maturity and composure that belied his age.

As they crossed Main Street, passing the library William had begun frequenting, Thomas slowed his pace. William could sense the shift in his brother's demeanor, the slight tension in his shoulders as he prepared to broach a sensitive topic.

"Listen, Will..." Thomas kicked a stone, hands stuffed in his pockets. "I've noticed you've been spending a lot of time alone lately. More than usual."

William's stomach clenched. His mind raced. Alone? Bullying? What the hell? Blimey, he had precisely zero context about this version of himself, this life's history! What was he supposed to say?!

"Those kids from Maple Drive giving you trouble again?" Thomas asked, his brow furrowed with concern.

A minefield. William chose carefully. Vague. Noncommittal. "It's... fine," he managed, hoping the slight hesitation would read as emotional vulnerability rather than total confusion.

Thomas stopped walking, studying him with those perceptive eyes that seemed to see right through William's carefully constructed facade. "You'd tell me if something was wrong, right?"

"Course I would." William met his brother's concerned gaze, offering a reassuring smile. "I promise I'm okay. Just going through some changes, I guess."

Thomas nodded slowly, his expression still tinged with worry. "Yeah, growing up's weird like that. Just don't forget you've got us, alright? Even if we drive you mental sometimes."

William felt a surge of warmth toward this protective older brother he was still getting to know. In his first life, his brother Thomas had always been there for him, but even now it seemed, some version of his protective older brother would remain.

"I won't forget," William assured him, reaching out to give Thomas's arm a gentle squeeze. In this new life, he was determined to be a good brother, to lean on Thomas's unwavering support and to offer his own in return. They were in this together, and William knew that with Thomas by his side, he could navigate the challenges of this strange, reborn world.

As they continued on their way, William couldn't help but marvel at the strength and resilience of his older brother. Thomas was no ordinary teenager, and William felt a deep admiration for the way he shouldered his burdens with such grace and determination. In this moment, he knew that he could trust Thomas with anything, and that no matter what life threw their way, they would face it together, as a family.

***

After accompanying Thomas at the supermarket for an hour and a 15-minute walk back to 'the Ridge,' the nickname he and his brothers apparently had for their house, William helped offload the groceries and bid his brother a silent farewell. The last hour-and-a-half was peaceful, but William was struggling to maintain his composure, the reality of losing his first life finally weighing down on him. 

William trudged up the stairs, his mind racing with thoughts of Hogwarts and the life he'd left behind. Thomas called after him, but William couldn't bring himself to respond. He needed to be alone.

He burst into his bedroom, slamming the door behind him. His chest tightened as he leaned against the wall, struggling to catch his breath. This couldn't be happening. Hogwarts? Magic? It was all too much.

William slid down the wall, hugging his knees to his chest. Tears pricked at the corners of his eyes as he thought of his old life. His family, his brothers, Jake... God, Jake. The one person who truly understood him, who stood by him through everything. And now he was gone, lost to a time William could never return to.

A sob escaped his throat, and he buried his face in his hands. How was he supposed to do this? How could he leave everything he knew behind and start over in a world that shouldn't even exist?

A knock at the door startled him. "Will? You alright, mate?"

William hastily wiped his eyes. "Y-yeah, I'm fine. Just need a minute."

"You sure? You looked proper gutted when you ran up here."

William took a shaky breath. "I'm fine, Tom. Really. I just... I need some time to process all this."

There was a pause, then a sigh. "Alright. But like I said, I'm here for you, yeah?"

"Yeah. Thanks."

William listened as Thomas's footsteps retreated down the hall. He knew his brother meant well, but this wasn't something he could talk about. Not yet. Maybe not ever.

He dragged himself to his bed, collapsing onto the mattress. As he stared up at the ceiling, a fresh wave of grief washed over him. His old life was gone, and there was no getting it back. All he could do now was try to make the best of the hand he'd been dealt.

But as he lay there, the weight of his new reality pressing down on him, William couldn't help but wonder if he was strong enough to handle it.

William wiped his face with his sleeve and took several deep breaths. Wallowing wouldn't change anything. He needed to be practical, to use this knowledge he had.

He pulled open his desk drawer, fishing out a fresh notebook and pen. His smaller hands felt odd gripping the writing implements, but he pushed past the discomfort. This was too important.

The blank page stared up at him. Where to even start? The Marauders would be first years with him. James Potter, Sirius Black, Remus Lupin, and... William's hand clenched around the pen. Peter Pettigrew. The traitor who would destroy everything.

He began writing, his handwriting messier than he was used to with these younger muscles:

"Marauders - 1971-1978

James Potter: Quidditch, Head Boy, married Lily Evans, 'Prongs'

Sirius Black: Disowned, lived w/ Potters, wrongly imprisoned, 'Padfoot'

Remus Lupin: Werewolf, transformations in Shrieking Shack, 'Moony'

Peter Pettigrew: Animagus (rat), betrays Potters, 'Wormtail'

Lily Evans: Extremely smart, muggleborn, Harry's mom

Severus Snape: Bitter, cares for Lily, half-blood, possibly redeemable (?)"

William paused, considering how to organize the crucial information. He flipped to a fresh page:

"Horcruxes:

Diary - Malfoy Manor

Ring - Gaunt Shack

Locket - Cave (later Grimmauld Place)

Cup - Lestrange Vault (?)

Diadem - Room of Requirement

Snake - Not yet created

Harry - Not yet born"

His hand shook as he wrote. These objects had caused so much death and destruction. And now he knew where they all were, decades before anyone else would discover them.

He added more details about each location, security measures, and how to destroy them. Basilisk venom, Fiendfyre... He'd need to figure out how to access these things.

William glanced at his closed door, then tucked the notebook into the false bottom of his desk drawer he'd discovered earlier that week. This information could change everything - but he'd have to be careful. One wrong move could make things worse instead of better.

His head throbbed. There was so much more to write down, but he needed a break. He couldn't risk forgetting anything important, but he also couldn't afford to miss any details in his rushed state. He decides to leave the novel alone for whenever he may need the information in the future. After all, there wasn't much he could do to stop Voldemort at 11-years-old, and he wasn't sure he could trust Dumbledore or anybody else with this information. Besides, he wasn't even sure he was even in the same Harry Potter universe he knew about. 

No, Voldemort was a problem for another day, he decided.

Moving on, William pulled out the he supply list from his desk, scanning it for the second time. Wand, robes, cauldron, books... The list seemed endless, and he had no idea where to even begin. The instructions mentioned something about going to the Leaky Cauldron, but how was he supposed to convince his family to take him there?

He flopped back onto his bed, letter clutched to his chest. In the stories, someone from Hogwarts always came to help Muggle-born students. But when? And who would it be? His memories of the books were clear on the major plot points, but fuzzy on these smaller details.

The sound of his mother cooking dinner drifted up from downstairs, along with Thomas's laughter at something on TV. How would they react when a witch or wizard showed up at their door? They'd already laughed off the letter as a prank. Would they slam the door in the face of whoever came to explain?

William rolled onto his side, eyes heavy. The emotional toll of the day - grieving his old life, making plans about horcruxes, and now worrying about Diagon Alley - had drained him completely.

"Tomorrow," he mumbled into his pillow. "I'll figure it out tomorrow."

His last thought before drifting off was wondering if McGonagall would be the one to visit, and if she'd turn their coffee table into a pig like she had for Hermione's family. That would be quite the sight.