John is absent in this, just like Zeus, in the end he makes the deal (spring summer - Demeter, fall winter - Hades) only to be rid of the nuisance, of his wife raking her dirt-stained nails through the fabric of reality, sending hail and droughts across the land, and his sulking younger son, letting rot set in to the destruction left in her wake.
Mary as Demeter, trying to keep Sam to herself, glad Dean's gone. Hating him, burning with righteous rage, because it's wrong, in so many ways, she can't admit to herself that her precious youngest is just as sick and wrong as her older boy, the one she forsook.
Dean, Dean who desperately tried to forget about his little brother, tried so hard, but when his parents figured out the way he looked at him he fled in shame, hid in the underworld both to be safe from his mother's wrath and to keep Sammy away from him, innocent, oblivious to the darkness inside his brother, his best friend, his supposed protector. He works his way up, works under both Thanatos (god of peaceful death - Castiel?) and Keres (violent death - Lucifer? Crowley?) and finally gets to rule over the souls they send his way.
Sam, who was never the same after Dean left. There's no longer a spring without freak snowstorms butchering entire fields, without frost sneaking up on bird nests, without loons calling out through the fog. Blaming himself for the way his parents treated his brother, his brother who never laid a hand on him no matter how much Sam wanted him to. Grieving him, because they told him he was in the underworld, that he was dead, even though a small piece of his heart still insists he isn't. Still yearning for him, still loving him.
The moment they meet again, the whole world shudders, knowing it will never be the same.
