The first week of life as a human was far too hectic for Castiel’s subconscious to really kick in; he went through the motions in a haze of new experiences, not really thinking about anything very much, happy to marvel in the newness of everything. But, after a week or so, things began to settle. He started to know what food he liked (anything that involved chocolate) and disliked (bananas were right out). He understood, at least in part, how to interact with Sam and with Bobby, and most of all with Dean. He became able to dress himself in his new clothes, and everything just seemed to plateau.
That was when he really began to think, not about human coordination and social skills, but about him. What he had been through, what it meant. He tried to remember being an angel, and realised for the first time just how quickly he was losing his memories. He knew it was bound to happen - Anna, after all, had had no idea she had been a fallen angel – but he was still not prepared for it. Although he knew he, unlike Anna, would always remember what he had been – the scars on his back and the handprint on Dean’s arm enough to guarantee that much – he was started to realise just how quickly he was forgetting the details. His brothers’ names were eluding him, at least for the most part, and the scriptures he used to be able to recite in every known language were fuzzy in the back of his mind.
He also became far more aware of his mortality, not helped by his attempts to help Bobby and Sam cook ending in a nasty knife cut to the palm of his hand. He had stared at the bloody wound for a long time, considering the pain and deciding he did not care for it at all. And, although he knew he would always choose a mortal life at Dean’s side over any other possible alternative, he began to find himself missing the safe comfort of his old Father’s embrace.
That revelation heralded the beginning of the nightmares. At first, they were too vague to cause him much distress: just dark figures and a general feeling of unease, but whilst he woke tense and confused, he found the feelings easy enough to shake off. Within the week, however, the dreams had taken full form, and he was being assaulted nightly by vivid re-enactments of his fall; his wings being torn from his back, his brother Uriel standing and sneering at him, being made to feel like one of Hell’s inhabitants in the eyes of those he had once loved.
Still, he tried to hide his private fears from Dean, did not want to cause him guilt. After all, Castiel knew that he would suffer far worse to be with the man. Dean did not need to know the particulars of the fallen angel’s suffering.
He supposed, in the end, he must just have become sloppy. One particularly vivid nightmare, the pain of his Fall so vivid he was near-convinced it was happening all over again, and next thing he knew he was shaking and sniffling in Dean’s arms, being rocked and hushed like an infant.
“Go back to sleep,” he heard himself beg of Dean, though the words held little conviction. His partner’s laugh confirmed that his request was falling on deaf ears.
“Tell me what you saw.”
Castiel just shook his head, immediately hating his hypocritical behaviour. He still remembered asking the same questions of Dean, back when he had still been an angel, as well as suggesting to Sam that he probed into his brother’s dreams and memories. He knew he should talk, but apparently that was a far harder thing to do when you were the dreamer.
“I... My Fall.” He said, simply, head dropping to Dean’s shoulder as he sniffed back tears. The tension he felt in his lover’s muscles confirmed to him that he had been right; Dean felt guilty.
“Cas, ‘m sorry...”
“Please, don’t be. It was my choice. I do not want you to suffer because of it.”
“I just want you to be happy...”
“I am.” The two words were said with an extreme vehemence, Castiel determined to prove to Dean that he regretted nothing, that he was right where he wanted to be. Sighing, he continued in a calmer tone. “Falling is... horrible, Dean. I doubt you can comprehend pain like it. It is not an experience I would wish on anybody. But I chose to suffer it, so that we could be together. So that I could be happy, feel happiness, with you. And I would do it again without thought. The dreams will pass.”
“No, Dean. No ‘still’. I love you.”
Dean sighed, sensing an argument he was not going to win. “I love you too, Cas.” He promised, resting back on the bed and closing his eyes.
Curling close into his partner’s warm arms, Castiel rested his head against Dean’s chest, eyes closing as he listened to the steady beat of the other man’s heart. This was what he Fell for, this warmth and closeness and love, and if a few sleepless nights were all he had to pay for this contentment? He would pay that gladly.