Castiel feels the power surge through him. Millions of souls, all with him, all loving him. Not powerless any more, not useless. Not alone. Never again alone.
The returning moon covers everything in shadows and traces of silvery light, and the souls roar, and swirl and there are so many of them, so many. So much chaos, so much confusion, and Castiel tries to call them to order but they keep pushing at his boundaries. He holds them tight, with him, all of them with him, none of them will ever leave him. He loves them, and they will love him, so why won't they just be calm, when they are all home now, and safe and him?
"Let go." a voice says. Just a single voice, beneath the millions that are part of him now, but so warm, so familiar, so loved, that Castiel can't ignore it. Can't but listen to it, and seek for it.
But they belong with me now, Castiel wants to answer.
"You can't hold them, Cas. It will destroy you. You need to let them go." the voice insists, and Castiel can't but comply. For some reason, he has to trust these words. He is so powerful now, but this is something so much more powerful than him, powerful and loving.
He loosens his grip and releases the souls. He feels them flowing out of him, leaving him, and he feels the loss of every single one. A small sob escapes him, when life and power is replaced by loneliness, and all that is left is one little angel in a vessel that suddenly feels too big to ever be filled by him alone again.
His legs give in, and only in a blur does he see Sam's attempt to leap for the angel sword on the floor and Dean's hand on his brother's chest to wordlessly hold him back. Castiel waits for the impact when he hits the concrete floor, feeling so vulnerable and weak that he is convinced it will simply shatter him into pieces. But the impact never comes. Instead he feels two strong hands catching him and gently lowering him to the ground, cradling him there, one hand supporting his head, while the other rests on his chest. Castiel blinks a few times to clear his vision, and finds himself looking into his brother’s blue eyes.
"Balthazar." he whispers.
"Don't worry, darling. I got you." the other angel answers with a warm smile.
"I killed you." It’s more than a statement, but Castiel doesn't know if he means it as a question or an apology.
"Well, yeah, you did. Sort of."
"How - "
Balthazar's smile grows a bit wider, and there is almost a hint of amusement in his eyes.
"Oh, Cas, my dear Cas, you still have no idea what Heaven's weapon are capable of, if you just know how to use them. Did you know about those sigils that actually allow you to commit your grace to another angel?"
"I don't understand."
"You see, I intended for you to stab me. It was the only way my grace could rise up and pass over to you. You know, so you at least had a chance to handle those souls without getting yourself killed, and half the planet right along with you."
"But you abandoned me. I was told - " Castiel's voice breaks with confusion and raw emotion, "I was told you had conspired with - that you were determined to stop me, to kill me. That you as well had betrayed me. That I had lost the only friends I had left."
For a brief moment Castiel wonders if he imagined Balthazar's gaze flickering over to where the three humans still stand, before the other angel's eyes are back on him.
"Yes, well, the rumours I leaked where pretty convincing, if I may say so myself."
Balthazar pauses, and when he continues, there is regret in his voice.
"I'm sorry, Cas. I'm sorry that I had to have you believe I was conspiring against you. There was no time for a better plan. I had to give you a really good reason to kill me, because without one you never would have. I know you, Cas. You love too unconditionally. That is what makes you so special, but it is also what makes you vulnerable."
Castiel lowers his gaze, and in a moment finds the hand on his chest gone, and cupping his face instead, warm, caressing his skin, seeking to sustain the contact his eyes broke through touch.
"I could never turn on you, Cas. I would never leave you." Balthazar sounds unusually soft and serious.
Castiel's eyes search for his brother's again, broken, hopeful, and pleading. "Where do we go from here, Balthazar? How do we fix this? How can I ever - "
This is when Balthazar laughs, a fond, affectionate laugh.
"This doesn't need fixing, Cas. We won. You won. Sure, Heaven needs some serious cleaning up. Again. Crowley is still out there somewhere and probably not too happy about your double-crossing him, you sneaky little angel. And I doubt that all those souls you set free went back where they belong, but that'll keep your favourite pets busy at least."
Balthazar bends down to kiss Castiel’s forehead.
"It's nothing you and I can't handle, Castiel." Castiel feels the words more than he hears them, his full name leaving Balthazar's lips almost like a prayer, a prayer not to a new God, but to a close friend, to someone beloved.
"It is really over then." Castiel sighs, when his eyes close and he lets himself relax and fall into warmth, and love, and familiarity.
"No, my darling Cas, this is truly a new beginning."