They hear it often, the sly insinuations. He was your boyfriend first. And, The angel who is in love with you. Dean always makes a face and Sam laughs.
Castiel doesn’t. He understands why the angels and demons say that. It’s the secret they’ve all been keeping for years now.
Because they can see it.
They can see the starburst gleam of Dean’s soul, still bright and shining despite his life. They can see Sam’s, shadowed with black and still gleaming, a shining obsidian flame, impossibly bright, almost in defiance of the fate written for him.
But the real secret isn’t the way the Winchesters shine like a sun brightening a black hole.
The secret is Castiel.
Angels don’t have souls.
They have grace.
Humans don’t have grace.
They have souls.
But if the Winchesters are soulmates–and heaven has known that since time began. Only soulmates could stand at the Michael Sword and Lucifer’s True Vessel.
Then Castiel belongs to them.
And they belong to him.
Never in the history of creation has there been a bond like the one the angel shares with the hunter brothers. But he dragged them from hell. And in doing so, he left his grace with them. Bits of the Righteous Man’s soul clung to him, star bright flecks of it that bound him to Dean.
It almost killed Castiel to feel Dean’s loathing and self hatred in those tiny pieces of self.
It almost killed him to feel the longing mixed with confusion when he stared at the angel for the first time.
He didn’t drag Sam’s soul from the Cage. He fought hard enough to rescue the body. But while Lucifer raged and Michael screamed, the angel touched the broken husk of Sam’s soul, soothing what little he could and pressing grace to the worst cracks and broken places.
It killed him, fleeing his brothers with only the body.
It killed him to feel the pain Lucifer rained down on Sam’s soul, and the way it curled around the bit of grace that he had left there, listening to the whispered promise.
I will come for you. We will rescue you.
He fought a war with his brother for the power to pull Sam’s soul from hell. Whatever else he said, Castiel would always know the truth behind his war.
Heaven knows. It’s why they pit him against the brothers so often. Why Hanna demanded Dean’s death as proof of his loyalty. Even hell knows.
Castiel is an angel and they are soulmates and they are his. Without having a soul, he has two soulmates.
It’s the best kept secret in heaven and hell and earth, and as he sits in the dark hotel room, watching them and their souls gleam, sun bright and obsidian dark and both flecked with the sapphire blue of his grace, he smiles. And watches his soulmates sleep.
This, after all, is what they are never given. What they may never have until they find heaven, together. And yet, this is how it should always be.