It’s a few weeks before Dean starts to notice things—subtle changes that take him by surprise and make him catch his breath, make his heart miss a beat for no real reason. Little things, normal things, human things. It takes a few weeks, but once he starts to notice them, he’s fascinated.
It’s the way Cas fidgets in his sleep and mumbles fragments of sentences, the way he always curls himself against Dean when they’re both in bed, but when Dean gets up he curls in on himself like he’s trying to stay warm. It’s his sleepy eyes and tousled hair in the mornings, and how he won’t speak to Dean before he’s had at least one cup of coffee, but if it’s past eight a kiss is an acceptable alternative.
He finds something endearing and irresistible in Cas’s small, sudden smile, and his rough, quiet laugh, which both come much more easily than when he was an angel; his habit of forgetting he’s eating mid-meal and sitting with his fork forgotten in one hand as he discusses some vitally interesting an important topic with Dean or Sam; the way he shivers when a breeze come through the window; the way when they’re pressed up against each other on the couch Dean can hear him breathing softly and see the rise and fall of his chest.
It’s the way he dozes off when they’re sitting watching TV and lets his head fall onto Dean’s shoulder, but he wakes up when Dean kisses the top of his head; and the way he yelps when Dean jabs his sides, which Dean knows for a fact he didn’t do before he fell.
When he thinks about it, it’s Anna’s words that come back to him—Anna, who fell because she would rather be flawed and alive than perfect and lifeless. Anna, who thought messy, dangerous, painful, emotional humanity would always be preferable to the cold, pristine light of an angel. Anna, who would rather be fire than marble or diamond, who would rather be ashes than dust.
Now, when Dean looks at Castiel and really takes in what he is now, his imperfections, his quirks, his humanity, he thinks maybe Anna was right.