Disclaimer: Not mine, don't own. Still want to sue? I've got some bills you can have.
Summary: With rituals nothing can go wrong, anything can go wrong, or both. You really don't want both.
Agony wrenched his soul apart. Tom Marvolo Riddle futilely clung to the cold stone floor, as though anything in his grasp would alleviate the pain. Someone poured boiling acid in his chest, or else he was having a heart attack because it felt like anguish was constricting the organ into a lifeless husk.
Reality was worse.
Reality was the shattering of his own soul—a creation not meant to be cleaved. His very being rebelled against it, taking more willpower than he had ever known to hold back; but though his voice grew hoarse Tom never wavered in his chant. Fear of mortality was stronger than even the final, horrible jolt of his very being split in two. Tears streaked down his pale face, the first he could remember shedding, but his wand remained fluid in its movements. For immortality, any amount of pain could be endured, even the torture of his own soul.
Then the pain stopped, leaving Tom breathless and twitching in its aftermath before the crumbling statue of his great ancestor. Only an odd hollow feeling echoed in his chest, swept away by the wave of elation that gripped him. After years of planning and a lifetime of being mortal, this day would mark a new beginning.
"The Chamber of Secrets…how appropriate that Lord Voldemort is born here," he thought, fingering an elegant black diary. Kept for six long years now and containing written proof of his true noble origins, it would be a suitable container for half of his precious soul.
The Horcrux process was not a particularly flashy one. Once the soul was split, all that was needed were the proper spells on the object to force the soul to adhere (already meticulously done) and the withdrawing of the soul-piece from his body. This last step was the truly dangerous part, for all soul magics are ritualistic in nature and nothing or anything could go wrong.
Nevertheless Tom was confident. He had carefully memorized every step he would take, every word he would speak, for he would not go down as one of those fools who died by their own idiocy.
He turned the yew and phoenix feather wand to his chest and began chanting…
But the feeling of his own soul, something deeper and purer and far more important than flesh, slipping out of his body was horrible in a way not even he could conceive. A sudden wave of possessiveness, stronger than even a mother's bond to her child, gripped him. His hand twitched in a reflexive move to take back what was his and the wand faltered. For just an instant.
Magic tore itself apart in fury. The backlash smashed Tom into one of the serpentine columns. Breath was forcibly ripped from his body. His heart stopped.
Moments later it beat again. Tom lay on the floor, eyes shut, gasping great lungfuls of life-giving oxygen and simply relished in the feel of his own life pumping through the organ. All his limbs were still connected, his vitals still worked, he was blessedly still alive. Trembling, he got to his knees, blinking aside the dust that the explosion had thrown up.
The faintest sound of gravel against boot alerted him to the fact that he was no longer alone…but who...? He turned.
Standing in the chamber was a scruffy youth about his age, shorter and decked in torn Gryffindor colors. For a moment Tom could only ponder the irony of one of Dumbledore's lions in Slytherin's famed chamber. Then shock and suspicion set in—what was he doing here and who was he?
Similar feelings flashed across a gaunt face, like that of a prisoner; a face that, for the life of him, Tom could not recall. He prided himself on his memory and though he was least familiar with Gryffindor students, he was certain he hadn't laid eyes on this boy before today.
The stranger knew him though. Recognition settled in as hardened green eyes scrutinized him. Abruptly the stranger came to some sort of conclusion and a smirk crossed thin lips, a smirk without humor.
Two words that said everything and nothing. Familiarity, bitter hate and dark satisfaction colored the tone of a boy he knew he had never met in his life; Tom nodded cautiously, irrelevantly wishing that he had chosen something a little more durable than paper for one half of his precious soul. That smirk grew wider, and more demented as the Gryffindor nudged his new Horcrux.
"Fiendfyre," he hissed harshly, almost like a parselmouth.
Tom very nearly retched when he heard the high-pitched, tormented wail that rose from the burning book. Theoretically he should have felt nothing but the reality of his renewed mortality sank cold, leaden fear in his gut.
The stranger turned with a drawn wand—where was his?—and Tom could scent bloodlust emanating off the youth. Why this Gryffindor student hated him ceased to matter. His shaking, scrambling fingers closed around familiar wood and he pointed yew at his enemy, a curse already on his tongue.
It was enough to reduce Tom's precious wand to splinters, and his hand with it. The heir of Slytherin gaped dumbly at the severed limb, survival instincts suppressed for just a second. Then he was up and fleeing, his very mortal heart rattling at the bars of its cage. Two more blasting curses took his knees out from under him.
"No Tom, not yet, you still have to pay."
Harry Potter raised his wand.