This was it. Not the Apocalypse, not the dark times that followed, not Purgatory. But this, this was the end of Castiel. The one time that an end is permanent. The only time it mattered. No resurrections, no penance, nothing. Just like that, he's no longer an angel. He had been prepared in so many instances to die or to fall but he always imagined a reason behind it. A purpose. A greater good. He knew someday his long life will come to a halt but he figured he'd always go down heroically. Maybe he'd die for Dean. Or Sam. Maybe he'd die in the hands of his brother, Lucifer. Maybe he'd rebel against Naomi and lose his grace for humanity. But never did it ever cross his mind that he would lose everything and everyone over nothing.
Castiel watched the sky lit with blazing balls of fire and he couldn't help but think how hauntingly beautiful they were. Like fireworks and shooting stars. It only served to break his heart in more ways because he had completely destroyed an entire population of God's creation. He felt his vision blurring as he kept his eyes fixed on the sky, unconsciously counting the number of falling angels. Unconsciously enumerating the devastation he had caused. Then, he felt wetness on his face that made him shiver a little when the wind blew gently, caressing him. Castiel touched his face and withdrew his hands when he felt tears. It was a foreign feeling. He never understood why humans cry when they're sad and why they cry when they're happy. He never learnt how to tell the difference. And the only good thing that came out of him being human now was that he could cry and empty the burdens in his heart. He could wash his sins in tears. Or at least, he could attempt to. So he wept helplessly. He fell to the ground and choked as sobs tore their way out. He wept till he felt his lungs constrict with the lack of air.
And in between his shuddering sobs, he whispered over and over again, "Forgive me, Father."