The end of the world came quietly. There was an earthquake that shook the whole globe as it swept and devoured every demon that cursed the ground with its presence. There were fireworks, a show of white lights scarring the night sky, shooting up to high heavens; each speck of grace returning home in glowing trails. There were monsoons of exhales, first conscious breaths in years, of freed lungs and minds, learning again how to live unpossessed. For seven billion people the world has started anew.
For Dean the world has ended with dead weight crushing his shoulders and his heart. He holds his brother's body in his arms on the cold, damp floor of a church crumbling around them. The wooden walls splinter in the jarring impact, crack and cave in, hovering roof stoops low to listen in on his grief, with a promise of a grand burial.
Each cell of his body aches to stay, his nerves melt into the surface of Sam's ashen skin; ripping them off threatens with opening up the blood vessels and bleeding him dry. If they opened, that would be mercy - he'd seep out into the floor, mix up with the rain. He'd coat Sam with his own last breath as he'd slip into death slowly, peacefully. His fingers dig deeper into Sam's hands, to the forearms that glowed with warm, heavenly light, like flashlights draining his batteries. When with explosion it exhausted itself, it exhausted him. There came words spilled from Sam's broken lips in harsh, foreign Enochian; and there was darkness.
It's in his eyes now, empty, staring off through Dean, the browns and greens, exuberant once, now swallowed by death. It's in the hollowness of his chest, filling in his still lungs and still heart. It creeps into Dean through the kisses he leaves on his brother's temple, adoring touch that hold no weight anymore. Sam's skin becomes wet from the tears of the sky and the tears of Dean's; Sam's skin is dried, lips cracked, tasting of sweat and blood and death.
He's got so many words caught up in his throat, that have nested there throughout a lifetime of being unspoken. He's got the itch in his fingers, squatting in his joints and hurting from restraint. He's got the ache in his chest burning with regret of never letting it out, while Sam's blood was still pumping, while his nerves could still respond to the lightest caress and reciprocate, take every embrace and every whisper into his bleeding heart, mend.
None of that matters anymore, and Dean could give all of himself the way he's been scared to all his life, but there's no one there to take, but the empty shell, skin stretched on the bones and muscles, devoid of the soul that was sold for the sake of his martyrdom.
At least Sam's fever wears off, warmth flees away between Dean's fingers and onto the endless night that has taken him away. There will be no gentle sunrise, flaring oranges and bloody reds licking their faces as they wake, no breeze creeping under their clothes, no last vow fulfilled. Even if Sam's begging cries will ring through Dean's heaven for the rest of eternity, there is no moving on for him, no saving himself from the rubble. The grief in his heart is too great, its poison too numbing to let his legs even move, to drag them both out; its drug like the sweetest song calling him to follow into the dark.
In the center of the universe, where Heaven and Hell shut their gates, an old church becomes a mausoleum. Dean holds his little brother's body against him, embracing the fragile, paper bones to shield them from the ceiling falling on them. With face buried in the crick of his neck, where no one can see him, inhaling the sweet smell of him, he doesn't even feel the heavy log breaking his back. For his brother he becomes Atlas who shoulders the weight of the armageddon, of sky falling down, until the planks don't pierce his lungs, until they are sheltered by a wooden temple where no one would come to pray for them.
At the end of the world they're intertwined, the solid shapes of their two corpses thaw into each other, become one. Outside of their pyramid of bones, the world new and reborn, heroless goes on.