[Wizarding World-year 1890]
[102 years before Gilderoy Lockhart became DADA professor at Hogwarts]
It was the dead of winter at Hogwarts. The stone corridors, cold and windswept, seemed to hum with an ancient, forgotten power. The icy chill of the Scottish highlands seeped into the very bones of the castle, bringing with it a foreboding silence. Even the common rooms, usually bustling with chatter and warmth, felt subdued.
Deep within the castle, far from the warmth of the common halls, there was a place known only to a few—a forbidden part of the Hogwarts library, concealed from all but those with a deep thirst for dangerous knowledge. There, amidst the forgotten scrolls and dust-covered volumes, sat Mercia Greengrass, a seventh-year student of Slytherin House, her eyes wide with an unsettling mix of fascination and fear.
Her dark hair fell in loose strands over a heavy tome she'd uncovered: The Arcana of the Founders, its pages yellowed with age, the ink faded and nearly illegible. She had been searching for something—though she could not have articulated what. Since her earliest days at Hogwarts, Mercia had always felt a tug toward the forbidden, toward things best left untouched. Perhaps it was her lineage, the blood of ancient wizards who traced their heritage back to the time of the Founders.
She ran her fingers over a drawing etched into the brittle parchment—an image of an enormous serpent, coiled beneath a castle. The words beneath it were barely visible, written in an archaic form of Latin. Mercia narrowed her eyes, struggling to make out the inscription, her breath frosting in the cold air.
"In hunc locum Salazar absconditus est, ex umbris aeternitatis regressurus…"
She translated slowly in her mind: In this place, Salazar hides, waiting to return from the shadows of eternity.
Her heart skipped a beat. It had to be a reference to the Chamber of Secrets—the same chamber that had been created by Lord Slytherin himself. This passage spoke of something deeper—something buried beneath layers of myth and history.
Mercia's fingers trembled as she turned the page, revealing a sketch of Salazar Slytherin himself—his gaunt face and cold eyes gazing out from the centuries. Beneath the sketch, more words appeared, smudged and cryptic:
"Nulla dies umquam, Salazar dicitur, nec mortuus nec vivus in aeternis..."
"Neither dead nor alive... Salazar lingers in eternity..."
A chill that had nothing to do with the winter night crawled up her spine. She had heard the stories, of course, like all Slytherins—tales of Salazar's desire to purify the school, his bitter feud with Godric Gryffindor, his eventual departure from Hogwarts. But there had always been whispers, even among the students, that Salazar had left something behind—something in the Chamber of Secrets.
"Mercia."
The whispering voice, soft yet cutting through the silence, startled her. She spun around, her wand at the ready, but there was no one. Only shadows, shifting faintly in the dim light of the library's flickering torches. Her breath caught as the darkness seemed to pulse around her. For a moment, she thought she saw movement—like a figure watching her from the distant stacks. But as her eyes adjusted, she realized it was only her mind playing tricks.
"Foolish," she whispered to herself, though the tension in her body did not ease. Shaking her head, she shut the tome, her mind racing. The text had been incomplete, fragmentary. Yet it was enough to stir something deep within her, an ancient curiosity that refused to be silenced.
Her heart pounded as she slid the book into her satchel, glancing over her shoulder one last time before stepping out of the restricted section. She felt it now—something was watching her. Something old, something waiting.
As she made her way down the dimly lit corridors, Mercia couldn't shake the feeling that she had stumbled onto something more than a mere legend. She thought of the old Slytherin families, of her ancestors, and of the ever-present sense of duty that came with being a descendant of one of Hogwarts' most illustrious houses. It was no longer just curiosity that drove her—it was something far more primal, a call echoing through the generations.
The heavy weight of the ancient tome in her satchel pressed against Mercia's side as she made her way back to the Slytherin common room. The dimly lit, subterranean corridors seemed to close in on her as she moved deeper into the castle. The damp, oppressive air carried the faintest scent of mildew, but tonight, it felt almost suffocating.
The common room was nearly empty, as most students had long since retreated to their beds. A single, flickering fire illuminated the room, casting eerie shadows on the green velvet furnishings and the serpentine carvings that lined the walls. Mercia's mind was still racing as she hurried to her dormitory, her steps quick and deliberate.
Inside, her dormitory was silent, save for the soft breathing of her sleeping housemates. Mercia's bed, with its dark emerald canopy, offered her a semblance of comfort, but her thoughts were already far from the safety of sleep. She pulled out the Arcana of the Founders, laying it gently on her lap. The cryptic Latin passages seemed to whisper to her, urging her onward.
Neither dead nor alive… Salazar's name echoed in her thoughts. Salazar Slytherin had not just been a brilliant, powerful wizard—he had been a visionary, and like all visionaries, he had left a mark on the world that transcended time itself.
Mercia's eyes scanned the text, her mind piecing together the fragments. There was another layer to the Chamber of Secrets, hidden beneath the very foundations of Hogwarts. And the text had provided her with just enough of a clue to find it.
The next night, after the castle had fallen into the hush of slumber, Mercia ventured out once again. Her pulse quickened as she made her way toward the depths of Hogwarts, descending stairs and passing forgotten corridors that even the castle's ghosts seldom traveled.
She carried a piece of parchment she had transcribed from the Arcana, containing instructions so old they predated any modern map of Hogwarts. It was a map of tunnels and caverns that lay hidden beneath the school—passages that had not been used for centuries. If the book was correct, there was one passage in particular that led to a forgotten chamber, lost to history. It was said that only a true heir of Slytherin could find it. But Mercia, descended from a line of old purebloods, believed herself worthy.
Her path took her deep into the bowels of the school, beyond the dungeons and below the Slytherin common room. Here, the stone walls grew colder, damp with the moisture of the underground lake that fed into the castle's foundations. The magic that protected Hogwarts felt different here, thinner somehow, as if she were stepping into a place untouched by the protective enchantments of the modern era.
Mercia's wand emitted a faint glow, guiding her through the twisting, ancient corridors. Her breath came in soft, shallow gasps as she approached a wall—seemingly solid stone, but with a faint, almost imperceptible marking etched into its surface. It was the same serpent symbol she had seen in the book, though weathered by centuries of neglect.
She hesitated only for a moment before raising her wand, speaking the incantation she had practiced under her breath.
"Aperire Serpentis."
The stone shifted with a low, grinding sound, as though the castle itself were awakening from some ancient slumber. A doorway revealed itself, a narrow passage beyond it descending even deeper into the earth. Cold air rushed from the opening, carrying with it the unmistakable scent of decay and something far more malevolent.
She stepped inside.
The corridor sloped downward, twisting and turning like the coils of a great serpent. As Mercia descended, the sense of dread that had been lingering in her mind began to grow. The walls seemed to pulse with some unseen energy, and she could almost feel the weight of centuries pressing down on her. It was as though she were entering the tomb of a forgotten god.
At last, the passage opened into a vast, domed chamber. The ceiling stretched impossibly high, lost in shadow, and the walls were lined with towering statues of serpents, their eyes gleaming faintly in the darkness. At the far end of the room, an enormous sarcophagus rested on a stone dais, its surface adorned with carvings of runes and serpents twisting around the figure of a man—a man whose face, even in stone, exuded a terrible power.
Salazar Slytherin.
Mercia's breath caught in her throat as she approached the sarcophagus. She could feel the ancient magic in the air, pulsing faintly beneath her feet, as though the chamber itself were alive.
But it was the figure standing at the base of the dais that froze her in place. It was no statue, no trick of the light, but a tall, spectral figure, its form shimmering faintly in the cold air. The ghostly figure was draped in long, flowing robes that seemed to blend with the shadows, and its eyes—piercing and pale—were fixed directly on her.
Salazar Slytherin's ghost.
A sense of dread unlike anything she had ever known washed over her. This was not like the benign ghosts that roamed the halls of Hogwarts—Nearly Headless Nick, or even the Bloody Baron. This presence was darker, heavier. His spirit radiated a power so ancient, so potent, that the air around him seemed to warp and twist, bending reality in ways that Mercia could not comprehend.
The ghost of Slytherin did not speak at first. Instead, he observed her, his cold, pale eyes sweeping over her form as though assessing her worth, her bloodline, her very soul.
"You've come far," his voice finally broke the silence, and it was deeper, more resonant than she had imagined. It was the voice of one who had seen the rise and fall of empires, who had lived and died in a time when magic was raw and untamed.
Mercia swallowed, her voice catching in her throat as she tried to respond.
"I—"
"You seek power," the ghost interrupted, his voice a whisper that seemed to echo off the chamber's stone walls. "As all of my descendants do. You seek the legacy I left behind."
Mercia could feel her pulse quicken. The ghost's presence was overwhelming, but beneath the fear, there was a pull, an undeniable attraction to the power he spoke of. Her voice trembled as she finally found the words.
"I seek the truth."
Slytherin's ghost laughed, a sound that sent a chill down her spine. "The truth?" he repeated, his voice dripping with disdain. "The truth is a weapon. The truth is power. And power…" His eyes gleamed with a cold light. "Power belongs to those who are willing to seize it, regardless of the cost."