Missing Star
When Castiel had entered his vessel Jimmy Novak he had not expected to be overwhelmed by pain. The pain felt to Castiel as if he was drowning, but it also felt oh so good. Familiar and comforting to his vessel's body, this had been going on for years and it seemed as if his vessel's body had no other way of knowing what was real or not without the pain that coursed through the flesh and blood.
Castiel, Angel of the Lord and of Thursday, felt despair at the life his vessel had lived. He flew away from the man's broken home and sat upon a cliff over the ocean. It was Castiel's favorite place to get away from the fighting in Heaven when he was a fledgling. He focused on his vessel's pain and dived into the memories of this man. A feeling of drowning in a sea during a tempest, touching the bottom of despair overcame the angel. He shuddered and removed himself from his vessel's mind, locking the man known as Jimmy Novak, up as tight as possible in the very center of the man's shattered soul.
It was surprising to the angel to see that the only person who ever realized that his vessel was in pain was in fact the human he had pulled from perdition and was supposed to guard. The only good emotion in the man was concerned with one Dean Winchester, Righteous Man and Michael Sword. Love, the greatest of all his Father's gifts centered on that one tainted human.
It was to Castiel a strange creature that stood before him. His vessel's memories and thoughts on this human, Dean, his vessel so helpfully reminded him, were so different from the man standing in front of him. Castiel buried the vessel's conciseness deeper because the angel could not stand the vessel's thoughts and emotions. Castiel was cold and unyielding in the beginning to the plight of the Winchester brothers. He had a mission after all. But then Castiel took to long periods of intense staring at the eldest Winchester brother and then he was in his space and then he was longing to be spoken to by this tainted man.
He began to believe in this human, that he could actually manage to stop his big brother's feuding and end all of Heaven's pain. Castiel ignored the fact that he had been in his vessel so long that he had begun to become his vessel, taking on his memories, emotions, and mannerisms. Castiel was an angel of the Lord and he would not fall to sin.
It was with shame and love that Castiel fell for the eldest Winchester brother. Castiel was drowning in the sea of what had been Jimmy Novak and he was losing himself beneath who the man had been. Castiel wanted to be everything for his Father, but he fought to be true to himself, like Jimmy had always wanted to do. Castiel became human in every sense of the word as he became a butchered version of the man that Jimmy Novak had been. Castiel was doing for his vessel Jimmy that Jimmy could never do for himself. Castiel died time and time and time again for Dean the man that they both loved. Castiel even became God to try and please Dean, to bring Jimmy back from the dead, but the souls killed him before he could even begin to try. The one thing Castiel regretted the most was not saving Jimmy and for failing both Dean and Jimmy. The Earth could burn as long as the two humans that taught Castiel everything and the human that loved him like a brother and helped him become more human was given joy and peace for all of the years he had drowned in that sea of pain.
When Castiel died after walking into that lake, he met Jimmy again. Like always Jimmy was curled up into a ball sobbing, but stopped and looked at him as soon as Castiel had appeared. The human, in the form of his child self, ran to him and threw his arms around the angel he had shared himself with for so many short years. He sobbed as the angel just let the human, his vessel and little brother, take the comfort he was so often denied in life.
"I've missed you Castiel! But you have to go back! You have to! You caused this mess to happen; now you have to fix it! But this time, I'll come back with you. God told me I could, because I was growing unhappy in my Heaven without you. I knew you needed me. So let's go back and fix this mess Castiel. Let's end it once and for all!" Castiel looked down at his vessel and with the first real smile he had used in a long time smiled at Jimmy. He nodded and wiping away his vessel's tears they once again became Angel of the Lord and vessel.
When they both came too after Dean had handed them his trench coat they went and saved Samuel Winchester because that was what they both thought would make the human the happiest. Seeing Lucifer was awful, but at least they had each other to fight the insanity. Castiel tried to protect his vessel as much as possible, but in the end they both succumbed to the insanity that had plagued the youngest Winchester.
It was better than drowning.