The sound of the world changing was not what Dean had expected. It was not the sonic boom of noise that he had always imagined. It was not the sharp crack of a bullet being launched down the barrel of his sidearm. It was not his, or Sam's pained screams as they faded for a final time into oblivion. No, it was the sound of something much more unassuming, but something much more devastating.
The sound of the world changing was nothing more than the rustling of fabric, rough and tan, smooth and white, creeping up to expose a pale forearm. It was the sound of a loyal soldier, defying orders, going AWOL in a way that was both unthinkable and inconceivable. It was the sound of a moment of eye contact between a man, and a being that anywhere else but in that realm was so powerful that to look upon it, or listen to it, would have destroyed him.
The sound of the world changing was the sound of cool, jagged metal whispering as it was exposed to the air. Metal that had once been the property of a very special demon, one that had squeezed her blood into the mouth and soul of the younger Winchester brother, creating an atomic bomb of flesh and bone that was hurling them towards a serious cosmic showdown. It was the sound of light catching, and clinging onto words etched into the blade, the sound of a palm wrapping around the wooden handle, worn smooth by use and age.
The sound of the world changing was the sound of flesh separating, layers of skin that had been whole only moments before as they tore reluctantly apart. It was the sound of knitted cells inaudibly screaming as they ripped and open, exposing muscle and bone, and the inner workings of human mechanics. It was the sound of disbelief as green eyes watched with a mixture of horror and wonder as thick, red blood bubbled out and out of the wound, greedily searching for the exit. It was the sound of a borrowed heart beating sharply beneath layers of clothing, a borrowed soul crying in pain and begging for this downward spiral to stop. There was still time, it said, time to turn back, time to heal the wound and pretend like this wasn't happening. That sound was slowly quelled by the sad coaxing of an angel who knew there was no turning back.
The sound of the world changing was the sound of fingers dipping into blood like grim paintbrushes. It was the sound of an ancient alphabet being smeared onto plaster and paint, each symbol drawn without a thought or a mistake. It was the sound of instinct controlling each finger stroke, each dip into the never-ending flow of crimson. It was the sound of a hunter committing every motion to memory as he watched each dismal character appear.
The sound of the world changing was the sound of an angel appearing, his voice sharp and angry, the name he uttered ancient and suddenly acidic on his vessel's tongue. It was the sound of a hand wetly smashing against the center symbol on the wall, unexpected and expected all at once. It was the sound of an inhuman scream, a room filling with light, and the creation of a vacuum that sucked the being into nothingness. It was the sound of borrowed time.
The sound of the world changing was the sound of an unspoken bond, a silent promise that from that moment on there would be no willful turning back. It was the sound of an army being formed, an army against all forces of Heaven and Hell. It was the sound of men who would be bonded through blood, through battle, through all the pain in the world. It was the sound of never being able to go home again, the sound of never being able to turn back. It was the sound of everything and nothing all at once.
The sound of the world changing was the sound of the end.