A/N: Apologies for the delay.

Leirad: Harry does not know the Summoning Charm, which Canon Harry doesn't learn until GoF.

The white king's pawn ground forwards two places.

"First. Who exactly are you?"

Professor Quirrell's shoulders straightened, and he appeared to consider the question.

"I am Professor Quirinus Quirrell, Lord David Monroe, Sir Jeremy Jaffe, Doctor Artadus Bunting, and a handful of others."

Professor Quirrell's gaze grew distant.

"As for how I came to be what I am... well. You are familiar, I know, with the Dark Art called Horcrux."

Harry nodded. He'd given some thought to how that spell could be used, if it could be engineered to use some different source for the death-burst, such as a magical creature. If a phoenix's regeneration superseded the power of a magical sacrifice, that was one potential option...

"I was David Monroe, defender of Britain. The Dark Lord was tearing the country apart, and if Magical Britain fell the rest of the world would surely follow. The Order could not hope to defeat Voldemort." The voice grew bitter. "I thought myself better suited, a Slytherin to counter a Slytherin."

Monroe's eyes narrowed.

"I was naïve. Albus Dumbledore was the only living wizard who could truly be called Voldemort's better, on top of that wielding the Hallowed Wand, called the Only One He Ever Feared. At no point was he anywhere near enough to match the terror that was the Dark Lord."

The beginnings of a sneer were playing about his face.

"I was a fool, a complete and utter fool. You wonder where I learnt my wizardry, boy? I pierced Salazar's Chamber, I spoke to his snake, I studied the Forgotten Arts. And when I was finished, I thanked the Basilisk courteously and left. I returned to the Chamber in my final year, to give my final thanks and goodbyes."

Then his voice was no longer contained, but cracked and vicious.

"I found the Basilisk's mouldering corpse! Beside it was a Penseive with a memory of Riddle gloating that he had killed the creature that only ever wished to help him, that Salazar had left as an unconditional gift to his heirs!" The aura of danger around Quirrell focussed into a pain in Harry's scar, and a light wind fluttered the elder wizard's robes around him.

"I make no claim to be a good person, Mr. Potter, but I like to think that I am not so empty as Riddle was even as a child."

A black knight fell from its granite horse.

Quirrell clenched a withered fist.

"And yet, I thought I could stand against Voldemort. Do you know what his plan truly was, boy?" he spat. "I learned of it later; you will understand soon enough. The Dark Lord was playing. I was powerful enough, courtesy of Slytherin's Monster, but utterly, hopelessly outmatched. Voldemort could have taken over Magical Britain within a week. But he had been bored, he was having fun... His plan was to allow me, David Monroe, to seemingly finally defeat him and take over Britain, and thence the world. But when he learned of the prophecy, he had no further use for me."

Quirrell sacrificed a pawn to the white queen.

He sighed. "In the beginning, I thought I could redeem Slytherin house. It says something rather profound that one thing I shared with the Dark Lord was an intense dislike of bullies. I would change that, become the Slytherin against whom all others would be measured." A short, bitter laugh. "And yet I was always a pawn of the Dark Lord, as I discovered one Hallowe'en."

Harry gave a small, involuntary step back at that. The tension had been rising, and Quirrell looked coldly, calmly furious. Harry had the uncomfortable notion that this was what his friends felt when he was angry.

"I knew the prophecy, and I had received intelligence that the Dark Lord intended to attack your home. I arrived on the scene to find James dead on the threshold, Lily fallen having tried desperately to save you." A touch of sorrow reached Quirrell's eyes, such an expression as Harry had rarely seen on him. "The Dark Lord used Lily's death to perform the Horcrux spell upon you. He planned, I believe, to thus destroy all but a remnant of you and remove the difference between your spirits, and set you up as a puppet instead of me. It did not end well for him."

"The resonance?"

"Yes. I am given to understand that the resonance is a side-effect of prophecy. As the Dark Lord wrought his spell, the turbulence began to burn him from the inside out. Just as I arrived, Riddle counterspelled my attempt at shielding as easily as I overwhelmed those bullies in the hallway, and then he cast aside his wand and tried to possess me, hoping to protect himself."

The white king moved to hide behind a pawn.

" I- I was caught up by the Horcrux spell. As he was trying to possess me, it was not the traditional overwrite, but a massive input of all that Riddle was..."

Quirrell trailed off, and took a deep breath. He looked old, and tired, and miserable. The Defence Professor had never shown such emotion in all the time Harry had known him. He gave Harry a measuring look.

"Mr. Potter... Harry. This- this is not a pleasant story, especially for you. This is one of the things I see when the life-eaters approach. And yet I know that you have seen things most will have the luxury never to see. You are no ordinary child. Even so, I will not blame you if you refuse to see this."

A lump rose in Harry's throat. It was the first time, the first time Professor Quirrell had ever used his first name.

From the dark robes came a small, grey stone bowl etched with odd runes, which settled on a conjured desk. Quirrell placed his wand to his temple and drew from it a thread of what looked like something between molten lead and Patronus light, which settled in the bowl, glowing faintly blue.

"It iss ssafe."

Harry swallowed, remembering the last Penseive memory he'd seen, Dumbledore losing his brother. He placed his hands on either side of the bowl, and leaned down until he fell into the memory.

The nursery was warm and brightly-lit and airy, yet it held a chill reminiscent of Dementors. Lord Voldemort stood over the corpse of a red-haired woman, tall and pale and terrible, tracing a spiral pattern in the air. The spiral was neither dark nor bright, no colour human eyes should have received, no colour a human brain could describe - it looked like the colour of something entirely colourless, with nothing behind it whatsoever, the same colour as what Harry saw out of his elbow.

Harry realised with a jolt that this was in part Voldemort's memory.

A small part of Harry noted that the Penseive showed more detail than Voldemort could possibly see, let alone remember, and wondered how to exploit that ability.

Black hatred surged in Harry as the Dark Lord touched his wand to Lily Potter's forehead and raised it to the swirling spiral of nothingness.

Lord Voldemort hissed in cadences older than Latin, "Sozdomai, ton phrenon emou sozdo..."

The beginning and ends of the spiral of nothingness glowed stark white.

The bone-white wand rose, touched the infant's head-

And then the far wall was torn away, a gust of wind blew freezing droplets into the warm room, and a man dismounted a broomstick and drew his wand in one smooth motion.

"I truly thought I might save them," came the soft voice of the modern-day Monroe from behind Harry.

Harry jumped and turned.

"I am... very sorry for what happened this night."

Harry nodded, not trusting himself to speak.

The young Monroe rushed towards the screaming Dark Lord, opening his mouth to chant Shield Charms-

Voldemort slashed his wand and released it mid-swing. Monroe's shields were torn away like so much tissue paper, the Dark Lord vanished in a black swirl, and Monroe collapsed, holding his hands to his bleeding head and screaming, screaming in two tones, alternately deep and human and high-pitched and demonic-

The spiral of nothingness flashed every colour and burst, setting every hair on Harry's neck on end and-

The nursery vanished.

The darkness coiled around him, and David was dead, he knew he was dead, life could not possibly contain such pain. Suddenly his head rushed, and he was assaulted with a thousand books, a thousand libraries, everything that was the Dark Lord, and it burned.

The scene changed.

The scraggly little rabbit was growing old. It had a bite taken out of one ear and its fur was falling out and most of its tail was long gone, but Billy Stubbs doted on it. It didn't take Legilimency to know that it was the only thing left in the world that yet loved Billy.

One day, Billy had shoved Tom Riddle at the dinner table, had taken the last of his favourite food, and when Tom had protested Billy had hit him, and called him a freak.

And Tom had listened to Billy's screams, and his sobs, and more screams every night when he had nightmares (always inexplicably vivid and consistent), after the rabbit was found hanging by its neck from the rafters, and smiled.

The scene changed.

"Go on, then!" bellowed the small, balding man. "Go on then, Tom! Kill me! Martyr me! I've lived a good life. More than anyone could say for you. You're pathetic. I'm not scared of you."

"Is that so, Yermy?" hissed a voice that might have come from the whistling wind or the crackling fires consuming the bolt-hole. "Is that so?" He waved a skeletal, spidery hand, and the Disillusioned, Silenced forms of three women were revealed behind him.

"No," whispered the old man, "No, no, NO-"

The scene changed.

The Dark Lord reappeared in the nursery, staggering.

Then the scene paused, and Professor Quirrell turned to Harry.

"The Dark Lord unwittingly imprinted his being onto me," intoned the modern Monroe grimly. His voice took on something like a professorial tone, though it was still strained. "Mr. Potter, when you heard of the Horcrux spell, what was your first thought?"

It took him some effort, through the numbing pain, horror and revulsion, but Harry thought back. "To improve it."

"And this Lord Voldemort had done. He had formed his greatest creation: an improved Horcrux. Legends suggest this may have been the original form of the spell. Regardless, each Horcrux granted him what might be called a soul: a constant non-physical embodiment of his being."

Something of a Riddle. "One Horcrux buried in solid rock," muttered Harry heavily, "One Horcrux sunk to the depths of the ocean. One Horcrux dropped into the Earth's mantle. One Horcrux flying invisibly in the sky. And one drifting forever through space, the Pioneer Plaque."

That wasn't quite as bad as it could be. There might be some way to track them, somehow, through the magical link that must surely exist in some form... and NASA knew exactly where the Probe was...

Quirrell seemed to gather himself, and his gaze turned sharp. "If you are considering the practicalities of a great quest to hunt down the fragments of the Dark Lord's soul, know that the spell has no great cost, merely a murder."

"I see," said Harry hollowly. "The Dark Lord made a Horcrux every time he murdered someone. Pebbles tossed in the sea, grains of sand..."

"Mr. Potter, this puzzle," Quirrell gestured to the tableau, "is soluble with your knowledge of magic. The Dark Lord Voldemort releases his possession and reappears before you, briefly dazed, and you are able to Stun him before he recovers. He has thousands of Greater Horcruxes hidden even he knows not where. If you kill him, he will return, and he will wreak the most terrible vengeance upon you. What do you do?"

Harry saw the solution instantly. What he'd been calling his dark side was just the echoes of the Dark Lord in his mind, and when he'd asked it what it thought of death...

The Dark Lord Voldemort had held such a terror of death that he had seized on his first solution and implemented it again and again, flinching away from the uncomfortable thought that it might be fallible.

A Muggle security analyst would call that fencepost security, like building a single mile-high fencepost in the middle of the desert. Nobody would try to climb it - they'd simply walk around it.

No number of Horcruxes would ever help Frank and Alice Longbottom. Thirty minutes under the Cruciatus Curse, and the Dark Lord would be gone forever. Or, even better, hit him with an Obliviate hard enough to make him forget his own name. The greatest Dark Lord in centuries could be destroyed by a first-year of Hogwarts.

"You Memory-Charmed him so hard that he lost his entire episodic memory?"

Professor Quirrell shook his head. "That would have been the better solution, but no. Not quite." His eyes were stony and still, his face seeming carven from ice. "Words cannot possibly express my feeling in that instant. Monroe's righteous rage, Riddle's cold fury..."

The memory-Monroe snatched the Dark Lord's fallen wand and hissed, "Stupefy." The scene froze again.

"Using two wands is dangerously unpredictable and inefficient, but I was beyond all reason." The words were quiet. "I had hated Riddle before. He murdered my entire House, and some he did not grant the mercy of the Killing Curse. I arrived too late, held them as they died... and yet never before I received his Horcrux spell did I feel such loathing."

The younger Monroe aimed two wands at the Dark Lord and shrieked, "CRUCIO!"

Harry watched, almost unseeing, as the Dark Lord writhed and twitched under the wands of Harry's friend's younger self.

It wasn't right, it shouldn't have happened, not even to him, not to anyone.

Quirrell's voice was soft, lilting, and Harry felt sick as he realised that this was most likely the best part of the memory for Quirrell.

"Before you judge me too harshly, Harry, listen. This is my worst memory, the worst memory. This night, I was made to be like the Dark Lord. Riddle had once tried to be happy. He was nothing if not sensible. He spent a great deal of effort trying to help people. He was Alexander Chernyshov, he liberated some tiny hellhole and its inhabitants wept tears of gratitude. For him, it felt like nothing in particular." Quirrell's voice dripped contempt. "I can still remember how it used to feel to help people, call to mind the warm glow. Sometimes I still feel it, to some degree. That plain indifference is the Dark Lord's curse, worse than any magic I or any other could cast on him. And that is what he gave to me. And that is how I cast one of the most dreadful curses and feel nothing."

Harry was frozen, he had no idea what to say, no idea what to think.

"I will not show you the worst of Riddle's atrocities. I am not a soft-hearted man, Mr. Potter, but sometimes I still wake from nightmares about what happened to Amy Benson and Dennis Bishop, when the Dark Lord was nine years old."

The memory faded, and Harry was standing once more on a tile of cool stone.

Harry wiped the sweat from his forehead. There would be time to process all of this later, time to rage and weep later. For now he could use his Occlumency and pretend to be someone impartial. He needed to learn as much as he could.

"What was the Dark Lord actually planning?"

The grim, stony expression remained. "The Dark Lord planned to have David Monroe appear to kill him, then touch a Horcrux and become a puppet leader. As for why he did not effect this sooner... past emotions are difficult to untangle from the mess of Riddle's memories, but I believe he was simply enjoying the game too much. He felt invulnerable, and fell too deeply into the role he was playing. Dumbledore, you see, has not a Slytherin bone in his entire body, and yet he tries because he must. Dumbledore brings to his task the Elder Wand, the Line of Merlin Unbroken, a phoenix, some source of foreknowledge, magic beyond any seen for three hundred years, intelligence, dedication, and an utter lack of talent. For that reason, he is marvellously difficult to predict."

Harry's throat felt dry. Somewhere, the Sorting Hat was screaming at him. The thought had finally occurred to Harry that his unreasonable hatred of Dumbledore had come from the imprint of the Dark Lord, and indeed, when he'd queried his dark side he'd found burning hatred and contempt. I think, said Hufflepuff, you owe someone a very big apology.

Quirrell's lips thinned. "The Dark Lord's little game broke five of my rules at first count, which is generally too much no matter how much fun one might be having, but I suppose he thought he stood to lose little."

The white king was hemmed in now.

"Another question, Professor. Who killed Hermione? The wards identified it as you." Please don't let it have been you, if you killed Hermione I want to believe you killed Hermione, please don't let it have been you...

Professor Quirrell set his teeth. "I did not succeed in what I did to the Dark Lord, Mr. Potter. "

"Of course you didn't. It would be purest optimism to assume the Dark Lord is no longer a threat, just because he was Cruciated into insanity and burned to a crisp..."

"The Dark Lord was the greatest Occlumens in all recorded history. Merlin himself would have been unable to pierce his mind. Somehow, he managed to ignore the curse long enough to fake catatonia. Like a fool, I approached, and he seized his wand and poured the scraps of his magic into a blasting curse that vaporised my body and blew the roof off Godric's Hollow, but burned Voldemort as well. He expired shortly thereafter. As a partial copy of the Dark Lord, I was protected by the Horcruxes. It was then that I found that the great creation was imperfect. I could not float free, but was shackled to Horcruxes that the Dark Lord had hidden even from his own eyes. I was trapped amidst the stars for years. I did consider going mad, and sometimes wonder that I might have. The stars were my greatest comfort, for it is their nature too to burn, lonely, in the night."

The blank look on the Defence Professor's face was unnerving. "Eventually, almost two years ago, a man named Quirinus Quirrell found a Horcrux hidden in the folly of Riddle's youth, when he hoped for immortality by hiding lesser Horcruxes behind tests of skill and might. Quirrell was a Muggleborn adventurer, come to seek his fortune, with a vague fallback plan of teaching Muggle Studies at Hogwarts. I had more presence of mind than the Dark Lord's shade, and seized control. I suppose I shall owe Mr. Quirrell an apology when I can create a new body with the Stone, though this is something different from true possession and I doubt he will be permanently harmed."

A pang of sympathy for the original Quirrell tore through Harry, although he supposed that it was technically justified to steal someone's body for a few years, to escape eternity trapped alone with Voldemort. "So Voldemort..."

Professor Quirrell sighed, and he seemed to diminish somehow. "Nobody is immune to mistakes, Mr. Potter." He traced a symbol in the air with one unbroken finger movement, a triangle containing a line bisecting a circle.

"Thinking the Dark Lord truly lost, I sought the Resurrection Stone when you showed me its symbol. I found it upon a ring that Voldemort had long ago made into a Horcrux - by sheer chance, he had targeted the ring, not the Stone - and hidden in the ruins of his grandparents' home."

The foul bird in the corner fluttered its wings.

"In retrospect, I ought to have burned the place to the ground with Fiendfyre and then sought the Hallow, which may have escaped even that curse, and yet I learned too late the value of unsubtlety. Some curses, such as the Parselmouth curse, are more effective and easier to cast if they bind the caster as well. The Dark Lord, clever even as a youth, had cursed the ring to compel any who came upon it to covet it, to protect it, to wish to own and use it for themselves, bypassing any shield, and had made up for such a powerful effect by having it apply to himself tenfold."

A sick feeling was growing in the pit of Harry's stomach again. I'm sorry, Headmaster. "The curse identified you as the caster and overwhelmed you. You made the Resurrection Stone your Horcrux, and now, with its magic, the Dark Lord's shade can move freely. Voldemort possessed Professor Sprout, and framed Hermione, and set the troll on her."

Professor Quirrell nodded gravely. "The Dark Lord is half-mad, Mr. Potter, but still not stupid. He strikes blindly at you. He Transfigured the troll from the cloak I was wearing on the day the Headmaster identified me to the wards, and used an old ritual to transfer a true troll's magic to it."

Harry clenched a fist. "What way can you conceive to eliminate the Dark Lord permanently, Professor?"

"Further Cruciation. Obliviation. The Draught of Living Death. The Dementor's Kiss may suffice, although I doubt it. Dropping his wand into the pit of Azkaban, although that would only affect the Dark Lord if he had a body, and the wand would swiftly be broken down by the Dementors. Invoking some sort of truly greater, insurmountable magical effect may work, such that from that day forward the world would be without the Dark Lord... in fact, I think there may be something quite close by."

The white king was alone on the board, now.

"First we heal you, Professor. Then we resurrect Hermione, and then we make sure the Dark Lord never mildly irritates us again."

Professor Quirrell laughed grimly, and behind him, the bird of black fire spread its wings and gave a warped, crackling cry.

"And of course, Mr. Potter, what I have ssaid in thiss room iss no lie: am Horcruxx-copy of Dark Lord imprinted on pureblood-lord-hero, greater Horcruxxxesss presserve Dark Lord copiess ssuch asss mysself, Dark Lord livess, half-mad, he attacked girl-child friend."

The cry came once more, louder.

Harry nodded curtly, and stepped onto the back rank, trapping the king. "Checkmate."

The white king's crown fell at his feet, and the next door swung open.