He feels it the moment it happens. Quick; like a band-aid. But it’s worse.
Because it’s not the feeling of a human life ending. It is the feeling of a soul ripping its way out of a vessel.
And it’s a feeling he’s felt before.
Sam is small, so very small, and so confused. He is alone and scared, and it’s dark where he is, and he’s so cold. The cold more than anything is what hurts; raw and exposed, right at the core of him, nothing to shield him. He is exposed and he is vulnerable and he is naked.
He has never been this cold.
Lucifer sweeps the Cage the instant he feels that tiny spark within its boundaries. He is infinite wings and intent, and when he finds that tiny light of Sam’s soul, he wraps himself around it and shelters it from the storm. He pours every ounce of love and mercy he possesses into keeping Sam alive.
He is angry. He is so angry.
And he reaches with his infinite wings, because he has never been this angry. He has never been furious like this. When he was thrown from Heaven, he felt betrayed, but this—this is fury. This is murder. And with his tattered Grace, he breaks the bars of the Cage, swearing that Sam will never have to return there again, not in life or death, and neither will Lucifer. He grabs Michael by the claws and rips him skyward from the depths of Hell, because there was never an angel dumb enough to encroach upon Dean, but if there ever was, Lucifer knows that Michael would do what he is about to. He leaves his brother on the surface, shaking and scared but alive, and he goes to claim what is his.
He finds the body of Nick. Angels possess living vessels, and the vacating of a vessel is not enough to damper a human soul. Instead, Nick is atrophied and vegetative, dormant in a hospital in Detroit, kept alive by machines breathing life into his lungs.
No longer. Lucifer fills up the hollow spaces and settles Sam directly in Nick’s heart, letting that human spark of life take over and kick Nick into wakefulness. And then he slips in beside that tiny spark of Sam and tears every major muscle when he moves Nick’s body against God and biology and the realm of what is possible and what is so far from a miracle that it’s just pure spite.
Nick’s feet are bare against tile floors and he leaves bloody footprints. Lucifer is exhausted—too tired to fly, so he walks.
Each footstep freezes the ground beneath him. Each step leaves tremors in the earth. Storm clouds form above his head and spit lightning, crackling with the depth of the rage of an archangel. All the while, he bleeds. He bleeds from his broken feet, bleeds from where his Grace tears through fragile human hands, bleeds from the ever-present wounds along Nick’s hairline, bleeds from the corners of Nick’s eyes until blood drips from his chin. He doesn’t spare the power to keep the vessel held together with anything more than the barest threads. Instead, he funnels his power to Sam and feeds him, nurtures him, and prepares him for another impossible transplant. It is imminent.
He searches out Sam’s body because his cells are still a beacon to Lucifer’s Grace. When he feels the intruder inside, he sneers; he will later learn that an earthquake shattered San Francisco right around that time.
Gadriel. The Serpent, the real Serpent, wearing the skin of Lucifer’s God-chosen. It is blasphemy of the highest degree.
Lucifer suffered in the Cage in the dark. Gadreel was locked in a vault in Heaven—and only after Lucifer was cast down for sins that were not his own.
He had not ruined Eve, but he had been punished for it. He had tried to save what was left of the broken woman calling herself Lilith, and had gotten an abomination for his efforts—and a front-row seat to God’s favorite punishment.
Lucifer has more than one bone to pick with Gadreel, and all of them belong to Sam Winchester.
He follows a trail of exhaust particles to the bunker where Sam made his home, and tears into the wards that keep him out. They will not stop him now. No one will stop him in this.
And then he follows the indignant fury to the dungeon. He does not care for the crowd of Dean, Castiel, and some lackluster demon, and despite the gun that is pulled on him, Lucifer does not slow. He feels some satisfaction in the way the blood drains from the imposter’s stolen face, but rage in the way that some bloodstains remain. As if torture will force him out and save Sam, though Sam is no longer there. In a way, Gadreel has done him a favor in holding the vacant vessel together.
Lucifer will give his thanks most ardently.
“Brother,” Gadreel whispers.
Lucifer’s borrowed mouth is hardly capable of words. Instead, he manages a snarl with blood-frothed spittle clinging to his cracked lips.
He pays no attention as Castiel hauls Dean backward, offering him comfort in the words Dean, no, you can’t, he’s going to save Sam, only feeling some tiny calm that Castiel is observant enough to notice the flicker held in the broken body Lucifer possesses. That he cares enough, understands enough, to let Lucifer at the one that had not only broken Sam, but forced Dean to break a brother he was never willing to put anything but first.
Dean is flawed. In all honesty, Lucifer has never liked him. But he knows that Dean would always put Sam before himself. He will always do what it takes to keep Sam alive. He is human and he is selfish and doing it for the wrong reasons, but his love for his brother is real. It is... respectable.
Gadreel has broken something time-tried and true, and that is not something to go unpunished.
“Do not dare,” Lucifer finally forces out. “You do not deserve to call me family.” Gadreel struggles against his bonds, but they hold strong. Lucifer’s bleeding eyes look over Sam’s stolen body. “And he does not belong to you.”
“I have fixed him,” Gadreel hisses, eyes blue and alight and making Lucifer furious with the spoiled brat of an angel who dares to try to claim that skin as his own. “I have made him whole. He owes me his life. It was mine to take.”
Something breaks in Lucifer at the casual mention of stealing Sam’s life away. He snaps out an arm and wishes he could bring himself to cause physical pain, but he cannot. He cannot harm that precious, stolen body of his beautiful, broken boy.
He settles for tearing at Gadreel’s Grace instead.
Gadreel screams, and Lucifer muzzles him with a thought so he will not harm Sam’s fragile vocal chords. He does so like the boy’s voice, after all, and it does not do to allow such filth to ruin it.
“He is mine,” Lucifer whispers, comforting the timid little light of Sam’s soul with a pulse of affection. “He has been mine. He will always be mine. And when he is hurt, he will always return to me. What you took was not yours to take.” He lets his blood-blurred gaze slide to Dean, white-faced and tense to the point of breaking. “And it was not yours to offer, Dean, though I understand why you tried.”
Dean opens his mouth, but Castiel lays a hand on his shoulder, and he goes quiet. Castiel makes eye contact and nods to Lucifer.
Lucifer understands what it is to be attached to something fragile.
He wants nothing more than to see Sam safe where he belongs. It is because of this that he tears Gadreel out in one swift motion and a flare of azure light and consumes him whole.
Before Sam’s body can fall, Lucifer is there to hold him up, channeling Sam’s soul through his ruined veins and into the skin that belongs to his fractured soul. He feels Sam slip free and breathes a sigh of loss and relief, worshipping the steady heartbeat beneath his bloody hands.
And then he pulls away.
He does not want Sam to see him like this. Because in the end, Lucifer is a creature of pride, and he is vain. He knows that he is broken right now, and he knows that he will need time to recover, if he is to recover at all. He has yet to calculate if consuming Gadreel will have given him enough power to fix Nick’s body, or if he will waste away with the last of Nick’s living flesh.
If that is to be his fate, he only wishes to make Metatron pay dearly before he goes, and to attend to what little pieces of Heaven he can gather and carry Michael’s way.
For now, he is simply thankful that he has put things right. With a brush of bloody fingertips across his forehead, Lucifer knits together the broken bits of Sam and calms the tempest of his terrified soul. He will awake a short time from now, bewildered and blinking and knowing the truth but willing to trust in his brother for another infinite stretch of time. Sam possesses the kindness that Lucifer does not, but Lucifer does not envy him of it.
“Goodbye,” Lucifer says, silently adoring all the little ways that Sam has grown older, so fragile and human and infinitely precious, and Lucifer will wait until such a time as Sam can be happy in order to think of anything other than keeping him that way.
“You’re going?” Castiel asks.
“I would not expect you to understand,” Lucifer replies, stiff and internally bitter.
“No,” Castiel agrees, “But I do.”
Lucifer thinks that maybe he does.
He vanishes as Sam stirs.
There is a traitorous scribe that needs to be rewritten.