A blinding red light, black fire swirling around his hands, and horrible, horrible screams. They pierced the air like knives, exploding in horrible shrieking and moaning of unimaginable pain.
Dean tried to cover his ears and block out the terrible sound, the song of death, but the voices only grew in volume. The voices seemed to have no origin. They were everywhere and anywhere, including within himself. The horrible cries descended into maniacal laughter, taunting and teasing. "Stop, please stop," Dean pleaded. The voices laughed harder. Fire danced around him, but it didn't burn in the least. Dean swept his gaze over this new, hellish environment; toppled buildings, the remains of human and monster victims alike with permanent expressions of total fear plastered on their faces. And among them, almost unrecognizable, a hand draped over a crumbled cement block that wielded the broken handle of an angel blade. Dean rushes over, and had to turn away so keep from vomiting at the sight that greeted him. Castiel's body lay limp and broken over the rubble, his arms and legs mangled, and...
Two enormous raven wings sprouted from his shoulder blades, spread out over the ground. They were burnt and bent in several places, but they were no less magnificent. Smoke curled into the air in huge plumes. Dean stood, staring at the ground just in front of his fallen friend.
"I swear, whoever did this to you, I'll kill em. I kill them and kill them again, and a thousand times over."
Dean shuddered as he said this, his whole body trembling. But it wasn't with choking sobs, not sadness, but something else. Dean was happy. Why was he happy? He felt a smile creep over his face, a cruel, vile smile. Why, why was he smiling? His friend was dead, most likely everyone else he loved as well, and he was content. But why? How? Dean tried to hate himself for it, but couldn't find it in himself to feel any form of guilt. He heard movement, and opened his closed eyes. Castiel's head shakily rose several centimeters to look up at Dean.
"Dean, if you can hear me," his voice was weak, and he spit up blood after every few words. "If you can hear me, if you're even still in there, I'm sorry. I'm so, so sorry."
Castiel's eyelids fluttered and his head hung over the cement slab. Castiel took one last shuddering breath as his salty tears hit the ground silently, then he was still.
Dean nelt down and collected the angel in his arms. Dean stared into Castiel's pale face, void of life. Dean's soul whirled and thrashed within him with anger, the closest he could come to sadness. Killing Cas was awful, soul-crushing, but not feeling bad about it... Dean couldn't live with himself. But no matter how hard he tried, Dean could not feel guilty. As he held the corpse of his once best friend, what was left of the hunter Dean Winchester withered away with the remains of Castiel's grace. He let himself succumb to the darkness, for there was truly nothing left for him now.