I don't own them…
He opened the door, a familiar face looking directly at him. He never thought it would come down to this, having to do exactly what he was asked to do three years before. His hands were wrapped around the colt, a special gift from Castiel. The angel had become one of his closest allies since all the mayhem started. Him, Anna, and Bobby, but none of them could help him now; he had to do this on his own.
"Going to kill me, Winchester?" the familiar voice sent a spiral of chills up his spine. He had to do it, couldn't chicken out, the human race depended on it. So, hands shaking, he raised the colt and whispered, "I'm sorry," before pulling the trigger.
1 week earlier…
The light was blinding, but Dean ignored it as he tried to pull his brother out of the door. Then it all just stopped. Everything was still as the convent came back into focus.
"Come on, Sam," Dean muttered, breathing hard, still trying to push his brother out the door.
"Sammy's not here right now," Sam's voice replied. Before Dean could really register the words, he was hit in the face by a fist. The hit lifted him off his feet, slamming him into a cement wall. The breath was knocked out of him, making him involuntarily gasp.
"You know, Dean, I really must thank you. If you hadn't of started all this then I wouldn't be free. Of course, Sammy had a hand to." Lucifer, as Dean could only figure had possessed his brother, looked down at Lilith's dead body. "And Ruby, I guess." His eyes flicked over to Ruby's body, Dean having stabbed her moments before. "I gotta say, though, I owe you Winchester everything." Lucifer's eyes, Sam's eyes, flicked back to Dean, a smile on his face.
"Get the… the fuck outta him," Dean managed to get out. His breathing was coming back just not as fast as he wanted. Dean tried to get to his feet, but his legs wouldn't support him. Lucifer just rolled his eyes and hauled Dean to his feet.
Dean tried to attack, but Lucifer was too fast. He deflected the punch and used both Sam's strength and his own demonic powers to throw Dean into another cement wall. Besides the wind getting knocked out of him the second time, Dean also slammed his head into one of the bricks. He saw stars-I actually thought that was only in the movies-and tried to blink them away. He vaguely felt blood dripping down his face.
Struggling to stay conscious, Dean tried to sit up. A wave of nausea and dizziness sent him crashing back to the ground. The stars were replaced by black dots that threatened to take over. Amongst the black dots, Dean watched Lucifer cross the room. The demon-in his brother's body-crouched next to Dean's head and whispered, "I'm not going to kill you Dean. At least, not yet. You see, for a…I can't exactly say demon...a fallen angel I like to repay my debts. I really do. And you, my friend, I owe. You see you broke the first seal, you didn't kill your brother when you had the chance, hell you got rid of every obstacle that led to this. Plus, you died which brought out Sammy's dark side. Now, I know that's a lot to repay…" Dean drifted off cutting out Lucifer's speech.
"Hey, no sleeping yet," Lucifer said and shook Dean's shoulder. He jerked awake, feeling weaker than before. When Lucifer was satisfied Dean wasn't going to pass out again he continued, "I am going to start repaying that debt by not killing you. That should be enough for now."
Lucifer got to his feet, directing Sam's body toward the exit. Before Dean finally succumbed to the inevitable darkness, Lucifer turned around and said, "I thank you so much, Dean. Without you none of this would be possible. Your daddy would be so proud." Then he was gone and Dean was out.