Dean remembers the moment that Sam became his; his responsibility, his burden, his purpose. His to save.
It was also the last moment he believed that his father could do anything.
He's four years old and his arms are already tired from holding Sammy. He's heavy, even though he's just a baby. But Dean holds on tight as he stares up at the flames roaring from the window of Sam's nursery. He keeps waiting for his dad to come out, carrying his mom like Dean is carrying Sammy. He's scared of the fire but he doesn't yet know the fear of a world where your mother can be taken from you in the middle of the night, pinned to the ceiling and burned alive by something so evil it leaves wounds in the air of a room just by walking there.
Dean is a four-year-old who believes his dad is Superman. He can do anything, save anyone. Nothing can hurt his Dad. And as long as Dad's around, nothing will hurt him, either. Nothing will hurt Sammy, nothing will hurt Mom. He knows it like an instinct, like breathing. He knows it right up until his father sweeps out of the house and grabs him, pulling him away from the burning building and holding him too tight, staring up at the flames with him through eyes that suddenly look older and so, so empty.
He knows it until he finally understands that his mother is dead. Dean stops talking after that, for a long time. His father isn't Superman and there are things even he can't fix. The proof is in every morning Dean wakes up and remembers that his mother is dead.
The first word he says, when he finally starts to talk again, is "Sammy."
Castiel lives outside of time, at least as human beings understand it. He isn't eternal; he had a beginning and, eventually, he's sure he'll have an end. But still, as an angel he has experienced more time than a human could hope to fathom, and every second stands out in perfect, crystal-clear detail, like it just happened. One of the perks of being an angel. One of the few.
And just like he remembers the first fish to crawl out of water, he remembers the moment Dean Winchester became his; his choice, his direction, his purpose. His to save.
It's a room full of cold, blue light, protective charms from every religion in the world drawn on the walls and etched into the floor. There's a line of salt across the doorway. Castiel hears the gritty scrape of it on the bottom of his shoes as he steps over it and strides across the space to stand before the Righteous Man, to look on the one he pulled from Hell at last.
Looking through human eyes, onto a human form, is so different. For every physical ephemerality he can see there's a spiritual reality hidden from him. There are things in Dean Winchester's eyes that have no name, but a few of them Castiel can put his brand-new fingers on easily. There's fear fueling his anger, an underlying dread that roots deep and spreads to all extremities. Castiel forgives the attack before it happens, because he knows Dean can't possibly understand what has happened to him.
He will help him understand.
They exchange words. Dean asks questions. There is no gratitude there, only fear. When it dawns on Castiel why, he is actually shaken to his millenia-old core by it. He thinks perhaps he does a good job of hiding that.
Dean Winchester, the Righteous Man, the man who was never meant for Hell but went there anyway in order to save his brother, the man whose soul is bright with love and all its adjoining pain, and yet more love in full knowledge that it will bring more pain, the man who at his center burns so hot with both that his touch can leave scars on an angel's grace...that man doesn't think he deserves to be saved.
Castiel curses Dean's eyes for their blindness, and vows that he will help him to know better.
Author's Note: No original plot or anything interesting, just my thoughts and headcanons on the defining moments of my two favorite characters.