The scream still echoes in the minds of Game of Thrones fans years after it happened: the sickening crunch as Oberyn Martell’s skull exploded under Gregor Clegane’s armored fists in Season 4, Episode 8, “The Mountain and the Viper.” What happened to the Mountain after that horrifying victory? Many viewers assumed the massive knight would succumb to the manticore venom coating Oberyn’s spear, ending his reign of terror. Yet Gregor Clegane didn’t stay dead. He returned—silent, armored, and more monstrous than ever—as the enigmatic Ser Robert Strong. His transformation, role in Cersei’s schemes, and fiery final confrontation with his brother Sandor in the legendary “Cleganebowl” remain some of the series’ most shocking twists.
If you’ve ever wondered exactly what happened to the Mountain—how he survived (or was “revived”), what Qyburn did to him, and how his story ended—this comprehensive guide breaks it all down chronologically. Drawing from the HBO series, George R.R. Martin’s A Song of Ice and Fire books, and key episode details, we’ll explore the full arc of one of Westeros’ most feared warriors. Whether you’re rewatching the show, debating fan theories, or seeking closure on this brutal character’s fate, read on for the complete story.
Who Is The Mountain? Gregor Clegane’s Origins and Early Brutality
Gregor Clegane, known across the Seven Kingdoms as the Mountain That Rides or simply the Mountain, was a towering figure of terror long before his infamous duel with Oberyn. Standing nearly eight feet tall and weighing over 400 pounds of mostly muscle, Gregor was a freak of nature—strong enough to wield a greatsword one-handed while carrying a shield, and vicious enough to use that strength without restraint.
His early life set the tone for the monster he became. As a boy, Gregor brutally burned his younger brother Sandor’s face in a fire for playing with a discarded toy, scarring Sandor for life and creating the lifelong enmity between the brothers. Their father covered up the incident, claiming the injuries came from a bedding fire, but the truth fueled Sandor’s hatred and Gregor’s unchecked cruelty.
Gregor rose as a knight serving House Lannister, but his reputation was built on atrocities. During Robert’s Rebellion, at just 17 years old, he participated in the Sack of King’s Landing. Under Tywin Lannister’s orders, Gregor raped and murdered Princess Elia Martell before dashing her infant children against walls—crimes that earned him eternal enmity from Dorne and cemented his status as one of Westeros’ most reviled men.
In the years that followed, Gregor raided the Riverlands during the War of the Five Kings, burning villages, slaughtering civilians, and earning a reputation as a sadistic war criminal. His loyalty to the Lannisters made him indispensable, despite attempts to strip his titles (such as Eddard Stark’s declaration in Season 1). Gregor’s size, strength, and willingness to commit any horror made him the perfect enforcer for those in power.
The Trial by Combat That Changed Everything – Oberyn vs. The Mountain (Season 4)
The turning point came during Tyrion Lannister’s trial by combat in King’s Landing. Tyrion, accused of Joffrey’s murder, chose Oberyn Martell—the Red Viper of Dorne—as his champion. Oberyn had a personal stake: avenging his sister Elia and her children.
The duel in “The Mountain and the Viper” is one of Game of Thrones‘ most memorable sequences. Oberyn dominated with speed and a poisoned spear, wounding Gregor repeatedly while demanding he confess to Elia’s rape and murder. Gregor finally admitted the crimes in a rage, but Oberyn’s overconfidence proved fatal. The Mountain grabbed Oberyn, gouged out his eyes, and crushed his skull—declaring victory for Tyrion even as he fell.
But victory came at a cost. Oberyn’s spear was coated in manticore venom, a slow-acting poison designed to prolong suffering. Gregor’s wounds festered rapidly; his flesh turned black, pus-filled, and gangrenous. Maester Pycelle declared him beyond saving. Gregor’s screams echoed through the Red Keep as the venom ate him alive.
What Happened to The Mountain After He “Died”? Qyburn’s Dark Experiments
Cersei Lannister, grateful for Gregor’s role in sealing Tyrion’s fate, refused to let him die quietly. She handed the dying knight to Qyburn, the disgraced former maester known for forbidden experiments.
Qyburn took Gregor to the dungeons beneath the Red Keep. What happened next remains one of the series’ darkest mysteries. Qyburn claimed his methods would “change” Gregor—implying a combination of surgery, alchemy, and possibly sorcery. Gregor’s agony continued for days before Cersei announced to the small council that he had died. A cleaned skull—supposedly Gregor’s—was sent to Dorne as restitution for Elia’s murder.
Yet Gregor didn’t stay dead. He re-emerged as Ser Robert Strong, a silent, hulking figure in white Kingsguard armor. His face was hidden, his voice gone, his eyes reddened and inhuman. He no longer slept, ate, or spoke—traits that fueled fan speculation he was a reanimated corpse or lobotomized survivor. Qyburn’s “resurrection” turned Gregor into an undead enforcer, loyal only to Cersei.
In the books (A Feast for Crows and A Dance with Dragons), the differences are notable. Gregor’s skull is explicitly sent to Dorne after beetles strip the flesh, and Ser Robert Strong is introduced with hints he might be pieced together from parts. The show simplifies this: Robert Strong is clearly undead Gregor, with no skull substitution.
The Mountain’s Role in Seasons 5–8 as Robert Strong
As Ser Robert Strong (though often still called the Mountain), Gregor became Cersei’s ultimate weapon. He protected her during her walk of atonement, stood silent guard during key moments, and survived the destruction of the Great Sept of Baelor in Season 6—implying unnatural resilience.
His most chilling scene came in the Season 6 finale, “The Winds of Winter,” when Cersei ordered him to “confess” to Septa Unella behind closed doors, leaving her fate disturbingly implied. Throughout Seasons 7 and 8, Strong’s silence and brute strength made him terrifying: he beheaded Missandei on Cersei’s orders and stood as her last line of defense during Daenerys’ assault on King’s Landing.
Cleganebowl – The Final Confrontation with The Hound (Season 8)
The long-awaited “Cleganebowl” arrived in Season 8, Episode 5, “The Bells.” Sandor Clegane, having abandoned the Hound persona and found purpose with Arya, returned to King’s Landing seeking closure. He confronted his undead brother in the crumbling Red Keep.
The fight was brutal and symbolic. Sandor stabbed Gregor repeatedly, but the undead Mountain felt no pain. Gregor nearly overpowered him until Sandor tackled him through a wall, sending both plunging into the burning city below. They died together in flames—poetic justice for a lifetime of hatred and horror.
Many fans found the ending satisfying, delivering long-promised brotherly closure amid the larger chaos of Daenerys’ destruction.
Book vs. Show – How Gregor’s Fate Might Differ in The Winds of Winter
In the books, Gregor is officially “dead,” with his skull sent to Dorne, yet Ser Robert Strong serves Cersei. Theories abound: he could be a reanimated Gregor, a Frankenstein-like construct, or even someone else wearing his armor. Cleganebowl remains unconfirmed but heavily foreshadowed, with Sandor’s arc pointing toward a final reckoning.
George R.R. Martin has noted that characters who return from death are “changed”—losing parts of their humanity, much like Beric Dondarrion or Lady Stoneheart. Gregor’s fate may be even darker in print.
Why The Mountain’s Story Matters – Themes of Revenge, Monstrosity, and Redemption
Gregor’s arc explores revenge’s cost: Oberyn’s quest killed him and enabled Gregor’s monstrous return. It contrasts monstrosity with redemption—Sandor rejects his past, while Gregor becomes pure weapon. Fire, a recurring motif, destroys both brothers, echoing Sandor’s trauma and Gregor’s fiery end.
Frequently Asked Questions (FAQ)
What poison killed The Mountain initially? Manticore venom, thickened with sorcery by Oberyn to prolong agony rather than kill instantly.
Is The Mountain a zombie in Game of Thrones? Essentially yes—Qyburn’s experiments left him undead, silent, and impervious to normal injury.
Did Qyburn use magic to bring the Mountain back? It’s implied to blend science and dark magic (necromancy), similar to Mirri Maz Duur’s shadow magic.
Who killed The Mountain in the end? Sandor Clegane, in their mutual plunge into fire during Cleganebowl.
What happened to The Mountain’s head in the books? Sent to Dorne as proof of death, raising questions about Robert Strong’s identity.
Will Gregor Clegane return in the books? Likely as Ser Robert Strong, with unresolved theories about his true nature.
Gregor Clegane’s journey from brutal knight to poisoned victim, undead enforcer, and finally doomed combatant encapsulates Game of Thrones‘ themes of power, vengeance, and the loss of humanity. His fate—brutal, poetic, and fitting—remains one of the series’ most unforgettable arcs.
What do you think—did Cleganebowl deliver the payoff fans waited for? Share your thoughts in the comments, and explore our other deep dives into Westeros’ most complex characters.
