Cas' blood splattered onto Dean's face, warm and slick. Dean had pinned him down to the ground before he had plunged the first blade right into Cas' heart. Cas had gone down without a fight. All Dean remembered was the feeling of hunger, a hunger that could only be satiated when he took someone's life. The mark had throbbed on his arm, turning red and burning hot at the sight of the willing victim. He tried to fight it, but the impulse was much too strong. Dean's ears filled with the sounds of his own heart, throbbing with exhilaration and panic. He fought and fought with himself, but Cas didn't fight at all. Martyr that he was, Cas knew he had to die to heal Dean of the Mark of Cain. With tears in his eyes, Cas accepted his fate.
"Dean..." was the only thing that Cas had managed to say before Dean sunk the blade into his heart. Cas' eyes went wide in shock. His fingers clenched tightly around Deans wrist, as pain shot through Cas' body. This was the end for him. Dean felt Cas' body slowly go lax, the light gradually leaving Cas' wet eyes.
Dean's breath hitched. Reality dawned onto him. The sounds of the whole world flooded into his ears. Then came the tears.
"No..." Dean whispered, looking at Cas' lifeless form on the ground. He pulled Cas into his arms, whose head lolled from side to side as he lifted him off the ground and pressed him to his chest.
"No... no... no... NOOOOO" Dean screamed. He screamed in agony, he screamed with pain. He screamed until he was sore. Cas was gone.
"Come back to me Cas! Come back!" Dean yelled at Cas' lifeless body. "Open your eyes, you son of a bitch"
Cas did nothing. Dean yelled at the heavens, "Give him back to me! Like you always have! I need him..."
He looked back at Cas again.
"I need you Cas... I will always need you..." Dean whispered looking at Cas' face that was now stained with both of their tears. The colour was slowly leaving Cas' face, making him appear pale. Dean wiped the tears on Cas' face and ignored how cold Cas' cheeks felt.
"Cas..." Dean whispered.
"Cas... I love you... come back to me." But Cas lay lifeless in his arms. Dean slowly brushed his lips against Cas', hoping against hope that Cas would kiss him in return, but Cas just lay there limp and unresponsive.
Another blood curdling scream escaped Dean's lips and he hugged Cas' body harder than necessary. It was over. It was done. He had killed the love of his life.