Stain
Dean knew he needed to get his head in the game.
The Darkness hadn't killed them, or destroyed the Earth – yet. But he could feel it building on the horizon, gaining strength, biding its time. It was going to swallow the Earth whole.
Dean didn't know what it was waiting for, but he knew that it wouldn't wait long. If they were going to stand half a chance of stopping this thing they had to act now.
Normally he would be out there already, guns blazing, knives slashing, trying to do however much damage he could while fighting blind.
Mustering something akin to resolve and pulling on his boots was easy enough. But when his hand closed around the hilt of a knife he intended to stash in his belt, Dean saw flashes of blood and slit throats and dead eyes.
The sharp clang of metal hitting the ground snapped him out of it; the knife lay at his feet. He stared at the blood on his hands in horror, but when he blinked they were clean.
He gritted his teeth and clenched his hands into a tight fist, hoping to still the tremble in them.
The crunch of flesh and bone. Split skin beneath his knuckles. The shock in blue eyes.
Dean gave an inarticulate yell and lashed out at the closest object to him. It might have been a lamp, but as it smashed against the wall all he could see was Cas skidding across the floor leaving streaks of blood in his wake.
He slammed his fists on the table and heard the crack of impact as the angel's skull smacked into unforgiving hard wood. Again. And again.
Snap out of it! he ordered sharply.
He shook the fog from his head and his bedroom came into focus. Other than the broken lamp everything was in perfect order. Neat and tidy. The photos Sam had given to him were resting on his bedside table; a constant reminder of what he had almost done and why he couldn't go through with it.
Dean tried to convince himself that everything was okay, but of course that was utter bull crap because the world was ending and once again the Winchesters could claim full credit.
They had caused this mess. They were responsible for cleaning it up.
Ignoring the knife at his feet and the weakness it represented, Dean reached for his gun instead. He had been handling guns since childhood; using them was second nature and the familiar weight in his hand was usually a comfort.
But when he touched the barrel Dean saw terrified eyes go wide behind their glasses. The report echoed and a neat hole appeared in the kid's forehead. He toppled backwards, almost gracefully. When he hit the ground it was Sam in his place, young and frightened and desperate to leave the family business far behind him.
The Dean Winchester I know would never have murdered that kid.
Murder.
He was a murderer.
Not a hunter. Not a hero. Not saving people, or hunting things. Hunting people. Killing people. Murdering people.
Unconsciously he rubbed at his hands, but he knew the blood would never come off.
He had crossed a line.
People were dead. Rudy was dead. He had beaten the crap out of the best friend he'd ever had.
He wanted to blame the Mark.
But the Mark hadn't slammed his fist repeatedly into his brother's face, knocking him to the floor each time. Dean had resolved to kill Sam and the fist fight was supposed to awaken the Mark to make killing him easier. Once the bloodlust took over and he was seeing red, he wouldn't be in control of his actions anymore.
But when Sam held up placating hands and gasped "That's enough", Dean had stopped. Because the Mark wasn't in control. He was. He had done all of those things.
He had nearly killed Sam.
Dean couldn't look his brother in the eye without remembering how Sammy had looked up at him, terrified but trusting, loving him even as he stood over him as his murderer. Begging not for his own life, but for Dean to someday find his way back.
The Mark was gone, but if Dean Winchester had ever been a good man he was long since dead.
He didn't know what was right or wrong anymore. He didn't know where to draw the line between human and monster.
He had killed Death. In a way, he was death. When he touched people, they died. He wasn't a saviour, he was a grenade thrown into a crowd of innocents in the name of stopping an evil hiding in their midst.
But maybe he had been the one who was evil all along.
He knew what he was supposed to do. He was supposed to go out there and defeat the Darkness at whatever cost.
He was sick of the blood and the death and the violence.
But he picked up his knife and his gun anyway.
He spent an hour vomiting up his guts as he relived the deaths of every single person he had killed, but when he emerged from his room he was calm and steady.
People were going to die bloody. But if Dean Winchester was nothing but a weapon of destruction killing everything in his path, he was damn well going to take the Darkness down with him.