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In all the millennia of his existence, Castiel hadn’t given the concept of love much thought. Love just was. He never needed to question it, nor confirm its nature. Love took many forms, and existed in every shape and color.
Of course, he knew love in its biblical sense, too. God Himself was love. God created love so that it could grow, give meaning to the beginning, and form the foundation of existence.
It could be as simple as God’s unconditional love. Because Castiel loved his Father above all else, and he knew—without a doubt—that the Father loved all His children the same.
Then there was Jesus’ patient, kind, and humble love for his apostles. For all people.
And Castiel personally knew the straightforward, unwavering love for humanity. Their progress, and their ability to survive across centuries and millennia. Their persistence, their strength, their intelligence. Humanity was fascinating and unique. Flawed, yet somehow the most perfect of all His creations. In their imperfections, they committed sins, but they also built a beautiful world.
As an angel, Castiel also knew a kind of love for his own brothers and sisters, a protective instinct to guard his fellow warriors.
So, all in all, he knew what love could entail.
But it wasn’t until that day, sitting on a bench, that Castiel finally understood what love could also mean, how it could be different. Deeper. Human.
Humans have countless ways of showing affection, sympathy, or love. Sometimes it was a simple, familiar touch. Other times it was sharing gifts or secrets. Little things, like helping a partner out. Reassuring someone they didn’t have to face their problems alone. Carrying a heavy bag for an elderly woman coming back from the store. Or bringing home a drenched kitten to keep it warm.
There was young love, fiery and passionate. New and exciting, pushing people to act in ways that were utterly insane.
There was old love. Rooted in respect, belonging, forgiveness, and understanding. It was as warm as a well-worn sweater on a cold winter day, a sweater that smelled like cinnamon because there was pie baking in the oven. A little frayed at the edges, but still beautiful, still soft. A part of nostalgia, wrapped in good memories.
There was failing love, the kind that slowly withered away, unable to weather life’s trials. Doomed to fade.
There was love that burned for just one night passion, desire, and mutual physical comfort exchanged without expectation of anything more.
There was final, yet unrequited love. Steady, constant, but quietly tucked into the corner of one’s soul. Without self-deception, accepting it would never be returned.
There was maternal love, sisterly love, brotherly love. Families formed bonds beyond human understanding, willing to sacrifice their lives for one another without hesitation. And sometimes, family didn’t stop where shared blood began.
In many ways, Castiel’s love for Dean was all of these things at once.
Cas didn’t love Dean from the moment they met. It wasn’t love at first sight, like in those sappy movies Sam sometimes watched (and, of course, Dean too, though he’d never admit it out loud).
Even though Dean carried one of the most beautiful and brightest souls Castiel had ever seen, at first, Dean seemed brash, unbalanced, rude, and ungrateful. Bitter, stubborn, disobedient. Without a shred of reverence. Just a rough, jagged shell drowning itself in alcohol and hedonism. Castiel couldn’t understand how this rude, sinning, unpolished man could be the Righteous Man.
But then, Cas began to see what lay beneath Dean Winchester’s mask. That man wasn’t just a pretty face with a contagious smile and humor so juvenile it somehow always managed to amuse Castiel, worming its way into his heart. Dean was a man devoted to his family and friends down to every last fiber of his being. A selfless person who painfully underestimated his own worth, hiding his insecurities behind a tough exterior.
That mask had been part of Dean since he lost the support every child should have in their parents. But instead of receiving that support, Dean became it for his younger brother.
He was so self-sacrificing, strong, and principled that resisting his charm became impossible.
And, well, Dean’s cocky attitude, snarky comments, bold smiles, and Southern drawl certainly didn’t make things easier. Those only made him even more… charming.
Dean Winchester was a chaotic contradiction. Childish and joyful, brimming with humor and zest for life. Then suddenly stern, intense, and uncompromising. Outwardly, he pointed out faults in others, but deep down, he always blamed himself the most. He carried so much anger and frustration, yet still put everyone else’s comfort before his own.
One moment he was all grins and laughter; the next, he was fighting off anxiety and nightmares alone at night.
And anyone who knew Dean Winchester knew that emotions had never been his strong suit. Because no one had ever taught him that feeling and showing those feelings was pure human. That expressing them wasn’t a weakness.
So Dean clung to every new emotion with a vice grip, even though, deep down, he longed to do the opposite.
He was a paradox that Castiel had to solve at any cost.
At first, Dean saw Castiel as some kind of cruel joke. Though, over time, that changed into a respect that, in the beginning, teetered on the edge of fear. Angels were powerful beings, after all, and it wouldn’t do to underestimate them.
By the time they’d fought through the first—and then second—apocalypse, Castiel knew he’d earned the hunter’s trust. That he’d become one of Dean’s closest friends.
Despite the betrayals, and the harsh words thrown back and forth, they remained loyal. They fought. They apologized. They forgave. They shared failures but also tiny victories. That bond between them was unbreakable.
It was then Castiel began to sense there was something more. Though he didn’t yet understand what it meant, he started to grasp the weight of human love.
And eventually, it all became clear.
The feeling had started small. Subtle. An undeniable pull to protect this impossible man. And against all expectations, Castiel went against the current. Against his kind. His loyalty found a new target—one with striking green eyes and freckles dusted across his nose. Because that stubborn, snarky human had been right all along.
Then, for the first time in his existence, Castiel was given an incredible gift. Dean gave him a nickname. Just a shortened version of his name, but somehow, it was personal. It was deeper. A name unbonded from God.
For once, Cas was someone with his purpose. Not a soldier of Heaven. Not another angel blindly following orders. He was just Cas. Friend Cas. Brother Cas. Adopted by the Winchesters, defended by them at the cost of their own lives.
For the first time, Castiel mattered. And he had free will.
Loving Dean wasn’t hard, even if Dean himself could be difficult. That feeling grew slowly, quietly inside Castiel. He didn’t know when it happened. When friendship became affection. When admiration turned to longing. When devotion became love. The love drowns in every vein of his human vessel while seeping into his angelic grace. His very essence.
Every year spent at Dean’s side was a blessing. Castiel once thought love had limits, but it grew endlessly, spreading like vines, tangling and strengthening. Even knowing he could never have what he truly wanted, Castiel had never been happier.
Existing beside Dean Winchester was a privilege. A reward he didn’t believe he deserved.
Cas died in the happiest moment of his life. Knowing he was saving the one soul he loved unconditionally, without hesitation or judgment.
Dean didn’t need him to live. Castiel didn’t doubt Dean would grieve, but he also knew Dean was strong enough to move forward. To find his happy ending.
After all, that’s what Castiel wanted the most.
So his love… was kind. Humble. Patient.
And Castiel, the fallen angel, had the patience to spare.
Because he knew nothing mattered more than that bright, loving, and brave soul continuing to protect the world. And there were no more trustworthy hands than Dean Winchester’s.
Dean Winchester became the handprint that sealed Castiel's fate.
Marked on a human soul as surely as his shoulder. Twice, in fact. From that first moment to the very last.
And Castiel never regretted it. Not for a single second.