Night hung heavy over the Red Keep, a thick, breathless shroud that smothered even the usual murmur of guards on their rounds. Torches guttered low in their sconces, their flames whispering rather than crackling. It was the hour of the owl where secrets and shadows walked side by side.
Arthur moved through the stone corridors like a silent shroud given purpose. A half-helm borrowed, a tattered cloak, a purse quietly lightened of a few silver stags, such things eased his passage more than his name ever could. The King's justice might have held Gregor Clegane shackled, yet Arthur had his own justice to pursue. His own plan of revenge, one that the crown or the gods could neither order nor forbid.
Arthur descended a narrow stair, damp air brushing against his face as he reached the lower cells, closer to the belly of the keep, where screams never carried far. Yet he could hear the Mountain's screams echo through the stones. A single torch burned outside the guarded chamber. The two goldcloaks slouched, drowsy and bored. They barely glanced his way as he passed. Gold bought ignorance easily in the capital.
Arthur closed the heavy door behind him and stepped into the dim chamber, the single lantern casting long, wavering shadows across the stone walls. Gregor's bulk writhed against the chains, the great table beneath him groaning with every tortured shift of his weight. Sweat clung to the giant's skin in thick, sour layers. His breath rasped like a beast drowning in its own blood.
Gregor did not look up immediately; his mind, clouded by venom and fever, seized only upon habit.
"Give me the milk!" he snarled, voice breaking. "Do it now, before I crush your skull!"
Arthur let the door latch click softly and stepped closer, letting his steps be slow, measured. The lantern's glow revealed his smirk before it revealed his face.
"Do you want me to rid you of the pain, Clegane?" he asked, his tone almost soft, almost kind, almost believable save for the wroth beneath.
Gregor's head jerked toward him, and for a moment his fever-clouded gaze searched Arthur's face without recognition. He bared his teeth, a monstrous thing even now. "Do it now, you son of a bitch, or I'll tear out your heart and drink your blood."
Arthur stopped at the foot of the table, hands clasped behind his back in a posture of quiet control. The Mountain strained against his bonds, metal biting skin, chains rattling. His fury had not died, even if his strength was being stolen inch by inch.
"Calm yourself, beast, you do not deserve my blood," Arthur said coldly. "You'll crush no skulls. You'll fight nothing save for the shadows. By dawn, you shall not even lift your own head, not even take your breaths, in your own accord."
Gregor's head jerked, heavy eyes slitting open, recognition finally settling in his clouded mind. "You…" His voice was no more than a broken growl, ruined by pain. "Manderly… rat…"
Arthur stepped closer, boots steady on the stone. His cloak slipped back enough to show the hilt of Nightfall at his hip, the black steel drinking up the torchlight like a void.
"I see the poison has begun its work," Arthur murmured. "Good, I hope you are feeling the pain. Manticore venom, quite an exquisite thing, one expected nothing less from the Viper. Yet it was altered; if it had not been, then you would have already been dead. And we wouldn't have this little chat, you and I."
Gregor roared, or tried to, but pain cut the sound short. "I… Kill… you… all…"
Arthur regarded him as one might a diseased dog as he leaned nearer, his voice dropped to a razor's whisper. "You will not kill nor be killed, you are now damned Clegane. You will face my wrathful damnation."
Gregor's chains rattled as he tried, foolishly, to lunge. The motion sent him into a spasm of coughing, thick and wet.
Arthur watched, unflinching. "You feel it, don't you? The burning. The crawling under your skin. Prince Oberyn is a cruel man when it comes to vengeance."
Gregor trembled, veins bulging like ropes, breath hitching. Fury warred with fear in his eyes.
"But this pain?" Arthur stepped to Gregor's side, placing a hand upon the table as he leaned in close, meeting the fever-bright eyes without flinching. "This is nothing to what I have planned for you. And afterwards we will speak, Gregor Clegane. Of your past. Of your actions. And you will confess… because you'll have no strength left to defy me."
Gregor glared up at him, voice cracking into a raw rasp. "Go… to hell…"
Arthur replied, calm as a winter shore. "I may very well do so, yet not before I send you there."
"You bastard," Gregor snarled, chains clattering as he strained. "You think you're brave? Loose these chains, I'll show you what bravery is."
"You'll show me what fear is," Arthur murmured softly, "soon enough. "
From beneath his cloak, Arthur drew a dagger that shone like the color of dark wine, its blade etched with glowing red runes that pulsed like embers. The lantern-light caught the edges, making them shimmer with an unholy gleam.
Gregor stiffened.
Arthur tilted his head. "For now, little beastie," he said softly, "be as silent as you are able."
He crouched, placing the dagger's point to the stone. Runes unfurled from its tip like curling tendrils of smoke, only they were carved, burnt, and inscribed into the very floor of the chamber. Each mark hissed faintly, as though the stone itself recoiled from being touched.
Then Arthur drew the blade across his own palm, blood dark and warm spilling over his fingers. He let it drip, slow, deliberate, onto each rune as he circled the table. His voice dropped to a low murmur, the cadence old, heavy, and unnatural to the ears of mortal men.
The words slithered through the air like serpents.
Gregor froze. Then his face twisted, not in rage now, but dread.
"What… what are you doing?" he rasped, tugging at the chains. "Stop. Stop!"
Arthur did not look up. The runes drank the blood greedily, glowing brighter as they fed. The dagger hummed low in his hand. Shadows crawled across the walls in shapes that had no source.
Gregor thrashed. "Seven hells… STOP! My head… my head hurts… argh!"
Arthur stepped back at last, wiping the blood from his palm with practiced calmness. The runes encircled the table now, burning faint red, pulsing gently like a heartbeat.
He watched Gregor writhe and moan, clutching at nothing, eyes rolling beneath heavy lids.
Arthur spoke, voice soft as winter's breath. "It is only pain," he said. "And you have not yet begun to feel mine."
The chamber's torches guttered as Arthur whispered the next words, each syllable weighted with something older than men's memories.
A spark flared in the corner, bright, sharp, hungry.
It grew into a red, writhing flame that hovered above the stone floor, untethered to wick or wood. It hissed softly, like a thing breathing through teeth. It cast no warmth. Its glow was a wound in the world.
A flame made for promised blood, not sacred heat. For rotten flesh, not holy light. For eternal agony and damnation.
Arthur's voice dropped into the guttural cadence of the old tongues he had long since bent to his will.
"Ko'di raya chinnar ninte shar raya sora ninte."
The sound seeped into the walls. The air thickened. Even the shadows seemed to recoil.
Gregor went rigid with a sharp, unnatural jolt. His cries strangled into silence, not by choice, but by force. His jaw clenched, teeth grinding as if an invisible hand crushed his throat from the inside. His eyes bulged, bloodshot and wet, fixed on Arthur with naked terror.
Arthur stepped lightly onto the table, boots scraping the wood beside Gregor's convulsing frame. Coolly, methodically, he lowered the dagger and pressed its glowing tip to the brute's bare, heaving chest.
Then he carved. More runes, sharper ones, emblems of binding, of obedience, of compulsion. The kinds of marks once etched into the hides of things best left unnamed.
Each stroke sizzled, smoking faintly as Gregor's skin split beneath the enchanted steel. The Mountain could not even scream. His body quaked, rattling the shackles. Sweat and blood mingled on his skin like oil.
Arthur did not slow down. He murmured the final word, low, insistent, relentless. "Þjóna…" Another cut. "Þjóna…" A deeper mark. "Þjóna…"
The flickering red fire pulsed in rhythm with the chant, as if the flame itself fed on each utterance. Arthur leaned down, his breath cold on Gregor's cheek. "ÞJÓNA."
The runes ignited, red, then black, then red again. Gregor's limbs dropped, slack and trembling. His eyes rolled back for a heartbeat before snapping once more to Arthur, unfocused but fixed. The binding was complete.
Arthur stepped off the table, wiping the dagger on a cloth already stained with old sigils.
Gregor's shuddering ceased. His breath evened. The veins that had bulged with poisoned agony relaxed. His face, always a mask of brutality, became something far more chilling, empty.
Arthur tested the binding with a measured calm. "State your name."
Gregor's reply came at once, flat and hollow, as a corpse pushed into speech. "Gregor Clegane."
"Who are you?" Arthur asked, his voice cold.
"Your servant, my lord." Gregor replied evenly.
The words slid through the chamber like oil. The Mountain That Rides, breaker of men, spoke them as easily as a child reciting a prayer. Arthur saw the runes settling and vanishing, obedience taking root in bone and blood.
Arthur pressed further. "Did you kill your father?"
"Yes." No hesitation, no shame. Even the worst men paused when confronted with their vilest sins. But this beast will not. Not to him
Arthur stepped closer, the crimson fire painting his face in violent hues. "Why did you take his life?"
Gregor's eyes stared straight ahead, unblinking. "I struck down my father, for he sought to banish me to Essos, to waste away in a sellsword company among bastards and exiles. He wished to bestow our keep upon my cur of a younger brother. A fate I could not, would not, suffer."
The words were spoken without pride, without shame, without anything. Yet their content twisted something in Arthur's gut, a sour tightening behind the ribs. It wasn't a surprise, for he, too, had heard the stories that every man in the West whispered when no one was around. But hearing Gregor admit patricide as casually as one might recount breaking a horse was something Arthur had not encountered before.
No matter how many times he had used the runes, Arthur was still, even now, surprised by their unnatural powers. Arthur forced his breath steady, burying his revulsion and asked, "Did you kill your sister?"
"Yes."
Arthur forced himself to speak evenly. "I want you to tell me why you did so. Do you understand?"
"Yes."
Gregor's dead voice spilled the horrors of his past. The ones he had caused.
"I killed my sister, for she loved Sandor more than she loved me. She loved that ugly dog, always playing with him, laughing with him, all the while trembling at my presence. The cur Sandor, too, held her very dear to his heart, shielding her from my wrath, trying to be a shining knight from the songs. I could not abide their affection, their fear and hatred for me. So I silenced the bitch, drowned her in the well, to teach the puppy that none shall ever favor him over me. I whispered to the bastard at the funeral that no one would ever love a wretched creature like him now. No one would ever pick a scarred puppy over a prize hound."
A coldness slid down Arthur's spine. Not a shiver of fear but of grief, and a deep, certain hatred. He could see the young girl clinging to the only gentleness in her bleak life, only to be snuffed out by the brute she feared most. He pictured Sandor, younger, smaller, and helpless. losing the only light from his dark, hellish world. The tale unveiled more of the Hound's scars than stories and the dreams ever had.
Arthur swallowed the ache that rose in his throat. There would be time to mourn later. Now, he needed truth.
"Did you kill Elia Martell?"
Gregor answered without pause, without remorse, without even the shadow of understanding the magnitude of what he described. "Aye. I killed her and her whelp. I killed the whining whelp first. Then, with the bastard's blood still on my hands, I raped the princess. When I was finished, I cut her in half with a swing of my sword. Lord Tywin had ordered me and the rat Lorch to kill the royal whelps. And I made it happen. For duty and with delight."
The words hung in the chamber like smoke from a funeral pyre. Arthur stared at him, not as a knight, nor as a lord, but as a man confronted with the full depth of another's monstrosity.
Arthur's hand drifted to the dagger at his belt, fingers brushing the red-lit runes carved into its steel. A part of him, the human part, ached to end Gregor then and there, before the Mountain polluted another moment of the world with his existence.
But Arthur forced his fingers to still. Not yet. The spectacle was not over yet.
He breathed, slow and sharp, forcing the storm inside him to heel. "Do you regret any of it?"
"No." Gregor replied flatly.
Arthur sighed with weary certainty. "I had thought as much."
For a moment, he studied the monstrosity before him, bound by chains, silenced by sorcery, poisoned by venom, and still somehow not pitiable. Not even close.
"The pain in your body," Arthur asked, "do you feel it?"
"Yes."
"Does it still hurt?"
"Yes."
"It'll hurt much more, soon enough."
Gregor did not flinch, could not flinch, but the air around him seemed to tighten all the same.
Arthur continued, his tone calm, "The poison won't kill you now, not even if it reaches your blackened heart. Yet it will hurt a thousand times more than it did before. And you will feel all of it, with every heartbeat, with every breath. You will not be able to scream. You will not be able to ask for help."
Gregor's lips did not so much as tremble, yet Arthur felt his fear flicker beneath the spell's stillness.
"Your blood will boil," Arthur said softly. "Your flesh will rot. Your bones will crack and become brittle within you. Yet no one will see it, no one will smell the rot, and no one will feel the slow death except you."
He leaned closer, letting the words seep into the bound man's mind like a second poison.
"No one will even know of the wounds inside you, and no one will be treating it. Tomorrow, the grandmaester will declare you healed and able. The court will see a towering knight, ready to face judgment. And your final trial will begin."
Gregor's empty gaze met Arthur's.
"You will state you wish to confess before the crown. You will admit to killing your father and your sister. You will admit to killing Elia and her son. You will name Lorch as Princess Rhaenys's killer. And you will name Tywin Lannister as the one who gave the order."
"Yes. My lord. I will."
Arthur studied him for a long heartbeat, ensuring the bond held firm, steady as iron, unbreakable now that the runes were set. The Mountain would do as commanded. His final acts in this world would be of the truth filled with agony. A fitting end.
Arthur stepped back, drawing in a slow, sharp breath, letting the cold satisfaction settle into his bones.
"I will see you soon, Clegane," he said, turning toward the door. His voice was a blade with no warmth left in it. "And I give you my word, death will not be your relief. It will not give you any respite or peace. I shall see to it myself."
The flame guttered as he left, casting the bound giant into a pit of half-light and coming torment. The door shut softly behind Arthur, sealing the monster alone with the pain he had earned a thousand times over.