This is it. This is the end. They're trapped, cornered. No one tries to hide from the fact that's staring them in the face. There's no escape this time. This is their last hunt. They will fight, and they will die. There's no other choice.
So fight they do, but to no avail. Castiel sees it just as it happens, and he's not quick enough to stop it. The knife plunges into a boy's chest, then is yanked out. Sam falls to the ground, his pain unbearable but he doesn't let out a sound from it. Castiel tries to get to his side, but the path is blocked. He's stuck watching as the boy struggles to hold on to his life for even just a few moments.
Next to go is Crowley. With everything the demon has done to him, one would expect Castiel to rejoice at his death, but he feels no joy watching the electricity cackle as the demon-killing knife digs into him. No, because though Castiel never realized it, he'd begun to grow fond of the king during their numerous hunts with him. His witty comments and bizarre nicknames seemed annoying at the time, but Castiel is finding himself hating them much less now.
Castiel looks around frantically, searching for the one he's grown closest to in his time on earth. Castiel's eyes land on him, his heart suddenly filling with fear. He watches it in slow motion, but he's unable to stop what he knows is coming. He sees the knife as it comes into contact with his chest, and that's when Dean notices it. It's too late; the knife cuts through his skin like it was jello. Dean gasps as the knife is removed, his body thrown to the floor carelessly. The boy's hands grasp at his chest, but the pain is ever present.
This is the last straw for Castiel. Every second his eyes remain on the fallen boy, his anger grows, and as his anger grows, so does his strength. With power he didn't know he possessed, he pushes through the crowds of demons, each dying when they come to contact with his hands. Castiel doesn't kill them all. He would like to, but he can't. He knows his priority right now, and they are not the demons that are now fleeing the building in fear. It's the Winchester boys, only one of which still lives.
Castiel crouches next to Dean, taking his hand. Their eyes meet for just a moment, and that's all Castiel needs to start healing. But it's too late. Dean takes a deep breath, choking out three words Castiel has been longing to hear for years.
"I love you."
Before Castiel can say anything, Dean's eyes glaze over. Castiel chokes back a sob as he clings to the boy's lifeless body, willing him to come back. But he sees the reaper, and he knows all hope is lost. Once Billie gets to him, Castiel knows the boy is gone for good.
She looks down at Castiel, a hint of sorrow in her eyes as she says, "I'm sorry," before she disappears.
Castiel stops trying to contain his tears. They're gone. Crowley, Sam, Dean... They're all gone, and he's alone. He has nothing left for him anymore but sorrow and pain.
With a heavy heart, he reaches for his angel blade, putting the end to where his vessel's heart is. But he stops himself. He can't do this. He has to keep living, for his boys. For Sam and Dean, and even Crowley. For Team Free Will. He may not have been able to save them, but he can save himself. He can carry on their work. After all, saving people, hunting things. It's the family business, and the four of them are family. They've been there for each other through thick and thin. They are more Castiel's family than the angels were. So Castiel will carry on, and he'll do it for them.
And that's what he does. For one hundred years, he continues their fight. He drives around the country in Dean's Impala, his magic used only to repair it every time it breaks. It's not often that is does, though. The Impala is a trusted friend of the boys', and it rarely lets Castiel down.
He fights evil. He hunts demons, vampires, werewolves, wendigos; anything that kills gets killed. And he does it all day, everyday. It's become his life, his obsession. It's the one thing that can take his mind off the boys he lost while at the same time hold their memory closer.
But one day, it all changes, and it all starts with four simple words in his mind; the loudest Angel Radio has been in years.
The Winchesters are saved.
Castiel scans the newspapers, the Internet; anything that can help him find these boys. He heads down to the first case he sees; Lawrence, Kansas. It's over a day's drive, but he doesn't mind as long as he gets a case. It's a murder; so clearly a vampire that only a fool would know of them and not guess it. He approaches the police offers in the station, shows him a fake badge with a fake name. "Agent Winchester," the alias he uses on many occasions as a tribute to their memory.
"Is there a Feds convention or somethin'?" the officer jokes, leading Castiel to the other three FBI agents. "Agents?"
They turn around, instantly recognizable when Castiel's eyes land on them. They must recognize him as well, by their facial expressions. It's silent for a moment, the shock present. It's Dean that finally speaks.
"Cas?" he whispers.
Castiel just nods, not trusting himself to speak yet. Seeing this boy brings back so many memories; so many emotions he hasn't felt in a long time.
Dean throws his arms around Castiel, embracing him with all his strength. Castiel hugs him back, trying to grasp the idea that the boy is back. He takes a deep breath, trying to compose himself before he can say the words he has been longing to say for the last century.
"I love you, too," Castiel murmurs.
Dean lets out a slight gasp, looking down at the angel in his arms. "You remembered?"
Castiel nods. "Of course. I could never forget you."
It's those words that break the boy. Dean begins crying, though there's no one reason why. Maybe it's because he missed Castiel. Maybe he's relieved his angel remembers him. Maybe it's because Castiel loves him, something Dean was wishing he would say for the many years Dean knew him. But maybe it's just because he's back with the angel, his angel. And this time, he's never letting go.