It was the laugh. As ancient masonry crumbled around The Hound, he laughed, as his brother pushed his eyes so deep into his skull he could watch his brain liveblog the damage. He laughed because that was all that was left.
For seven series Sandor Clegane, or The Hound to those who tolerated or hated him, nurtured a deep hatred for his brother which even death couldn't mollify. Death was no impediment to The Mountain's hatred of his brother, either, this corpse exhibiting the first independent thought since his death in choosing to fight The Hound to another death. His first didn't make the The Hound's eyes sting with tears, but it must have eventually when The Mountain removed his armour. Dead skin and organs in a metal heat trap must be a tangy brew, headier than bottled condensation from the Central Line in summer.
As the old order collapsed around the Klitschko brothers of Westeros (what would their dear old mum say, brawling in public?), their savage reckoning reached a moment of enlightenment yet to trouble the royal rumblers of the Seven Kingdoms. Clegane, though, could now laugh.
A sword driven was through The Mountain's chest, a wound to be accompanied by a Michael Buerk voiceover, yet he continued. Numerous dagger blows by The Hound had the same effect. The Mountain continued, swatting aside pesky setbacks as if Theresa May. Then for perhaps for the first and certainly the last time, Sandor Clegane laughed. Years of hatred, years of resentment, years of dreamt vengeance, all that had defined him slipped away. Clegane, all too late, realised he didn't have to be here, duelling at world's end. Destiny was a fantasy he had spun for himself and he laughed at his mistake. The Mountain can't be killed (again) unless The Hound sacrifice himself in the process, tackling his brother into the fire, as The Mountain had pushed him into fire as a child. His hatred ended the way it began.
'You win or you die' was the hookiest of hooks for the first series of Thrones, which promised failed claimants and allies would be snuffed out without mercy. And that is how King's Landing fell - entirely without mercy. 'You can get further with a kind word and a gun, than you can with just a kind word,' says bagel salesman Robert De Niro in The Untouchables, an ethos shared by Daenerys, whose proclamations of enlightenment and justice are backed up by a giant airborne flamethrower. Fear is how she has chosen to govern, kind words saved for a favoured few.
For Clegane, victory included his own death; so it is for Daenerys, who finally killed off all versions of herself in choosing to complete what she convinced herself is her destiny. Her self-belief in her own legend doesn't allow for self-awareness, which is why Clegane's laugh was as striking as any blow. Winners still die.