A/N: Based on a prompt from Miyth.
Song: "Did You Hear the Rain?" by George Ezra
Setting: Season 11, AU
Characters: Castiel, Lucifer, Dean, Sam
Summary: There's a storm coming—the fight to free Castiel from Lucifer.
"Did You Hear the Rain?" - George Ezra
Oh, did you hear the thunder?
Or the rain?
Means I'm coming home again
Means I'm coming home my friend
Castiel wandered the facsimile of the bunker's library constructed in his head. He found it curious that his mind's prison would take this form. A subconscious attempt to shield him from the horror of his reality? Not that Castiel could forget for a single second that his vessel was currently being possessed by Lucifer. He'd said yes, after all.
The table started to rattle, and Castiel felt a vibration rumbling up through the soles of his shoes. A lamp flickered. He tensed as the pressure around him increased. Was the battle against the Darkness finally happening? Castiel wished he could catch a glimpse of the outside, but there were no windows in the bunker, and Lucifer had made sure to put locks on the door after Castiel had wrenched control from him that one time in order to prevent him from killing Sam.
The walls began to shake, sending several books tumbling off their shelves. Even shoved to the far recesses of his consciousness, Castiel could feel powerful magic snapping around him.
Lucifer came barging into the library, a torrent of rage and fury and crackling grace.
"What's happening?" Castiel demanded. "Is it the Darkness?"
Lucifer whirled toward him with a snarl and spat, "Winchesters."
A bright light filled the room, whiting out Castiel's senses.
Oh, did you steal my name?
Oh, you Jack of all trades
You're the master of none
Oh, the race has begun
I was born a champion
I was born to jump and run
When he came to, the bunker library was just as he'd left it, save for a few items knocked over from whatever violent spell had assaulted them. The shaking had stopped, but Castiel could feel magic encasing them, binding them. That couldn't be good.
Lucifer swung his arm at a lamp, flinging it across the room to shatter against the wall. Whatever Sam and Dean had done, the Devil was furious. Castiel shook his head; didn't they see they needed the archangel to defeat Amara?
"You shouldn't have broken cover with them," he muttered. As loathe as he was to have Lucifer masquerading as him with the Winchesters wholly unaware, at least it meant the Devil wouldn't actively try to kill them. They all needed to be focused on the Darkness.
Lucifer spun so quickly that Castiel didn't have time to react as a concussive force slammed into him, lifting him up and sending him crashing into the wall. Pain lanced down his spine as he hit, and then again when he dropped to the floor. His head throbbed with the reverberations.
"I will rend those putrescent little maggots, limb from limb," Lucifer seethed.
Castiel struggled to push himself up. "No," he grunted, lifting his head to glare defiantly. "You will not hurt them."
Lucifer scoffed. "You're weakening day by day, Castiel. Think you can pull that little stunt again? You can't. You don't have the juice."
Castiel got to one knee, then pushed himself up to standing. He drew his shoulders back and summoned his grace.
Oh, did you hear the rain?
Oh, the rain?
You can try and run and hide
Tearing at the chain
Oh, Lucifer's inside
Lucifer wiped the back of his hand across his mouth. It came away red. Fuming, he glared down at the stupid angel at his feet, now wrapped in chains and barely conscious, covered in a lot more blood than Lucifer was. Castiel had managed to weaken him, but it'd cost the little seraph dearly. Lucifer had been lenient before. No more.
He crouched down and grabbed a fistful of Castiel's hair, yanking his head back. "It's no use, Castiel," Lucifer crooned in his ear. "You chose this, and there's no escape." He leaned closer and whispered, "I was ready to simply kill the Winchesters. But now I think it will be more fun to torture them for eternity, with your hands, and make you watch."
Castiel shuddered beneath him, and Lucifer's mouth curled upward. All he had to do was escape the Winchesters' stupid trap…
The room began to shake and rumble, and Lucifer stood abruptly. What…? A mixture of white and red light speared through the walls, thrusting Lucifer back several steps. The chains around Castiel began to dissipate.
Lucifer's eyes blew wide as he realized what was happening, and he screamed as his consciousness was repressed and Castiel's was allowed to surface.
Did your siblings tell you
I was wasting up your time?
Oh, now you're wasting mine
You put me back in line
And I'm counting every link
And I guess you think that's fine
Castiel blinked blearily as waves of red danced across his field of vision. Heat wafted against his face, soothing at first, but then blistering. He jerked his head up, and everything blurred for a second. There was a clink of metal when he tried to move, only to find himself restrained.
"Cas?"
Castiel squinted as his surroundings gradually coalesced into solid shapes. He was sitting upright in a chair, with shackles around his wrists and ankles and chains covering most of the rest of him. A ring of holy fire simmered in a circle around him.
"Cas!"
He jolted at the harsh, desperate shout. "Dean?" he said groggily, looking up at the two figures on the other side of the fire. He recognized the bunker's dungeon. But how…?
Dean's expression looked wrecked as his eyes pleaded with Castiel. "Cas, listen to me. You have to eject Lucifer, now."
Castiel frowned. "I can't. You need him to fight the Darkness."
"No," Dean pressed urgently. "He already defeated Amara. The Darkness is gone. Now you have to cast him out!"
Castiel's brows furrowed further as he looked between Dean and Sam's haggard faces. The Darkness had already been defeated? Lucifer must have buried him deeper than he'd thought.
"We don't need Lucifer anymore," Sam jumped in. "Eject him so we can send him back to the Cage." He gestured to someone behind them that Castiel hadn't registered before. Rowena? Wasn't she dead? Yet here she was, standing at a table laid out with various spell ingredients. That must have been how they'd managed to wrench control of Castiel's body from Lucifer.
Castiel slowly shook his head as he roved his gaze around his surroundings, noting how securely they'd been captured.
"This is your chance to kill him," he said. "Once and for all."
Dean's face scrunched up in confusion. "What?"
Castiel settled back in the chair, feeling strangely exhausted. "I'm sure Rowena can figure out something," he said tiredly. "Cast a spell on an angel blade to make it more powerful. Lucifer is vulnerable like this, it will be easy to—"
"Kill him while he's wearing you?" Dean interrupted furiously.
Castiel nodded. "Yes."
Dean's nostrils flared as his face turned a deepening shade of puce. "And kill you too? Not an option, Cas! Cast him out!"
"Dean, you have to," Castiel pleaded. "This way he'll never be a threat again…" Castiel's whole body suddenly seized, and he grunted as he felt claws digging into his mind and trying to drag him backward.
Voices shouted around him.
"Cas? Cas!"
"Eject him, now!"
Castiel gasped as control of his body was violently wrested from him, and he found himself crashing down to the floor in the bunker's library again. Chains whipped out of nowhere and lashed around him. Castiel cried out as the links grew curved barbs that hooked into his flesh. Fire coursed into his veins with paralyzing poison.
Lucifer squatted down beside him. "Well, that was fun."
Castiel couldn't move without causing excruciating pain, but he managed to loll his gaze upward. "Did you already defeat the Darkness?" he gritted out.
Lucifer's face cracked into a grin. "What if I did? You didn't really expect me to give your vessel back, did you? You're not that naive."
No, he wasn't. But that meant it was time to fight back, to make sure Lucifer wouldn't end up being the next threat to the world. The Winchesters had already captured him, so that was good. But they needed to do what must be done.
Lucifer straightened. "You know, Sam and Dean seem more sentimental than I gave them credit for. Maybe if I threaten you, they'll let us go. Considering we're both chained up in their dungeon, I could let you surface a few times, let them hear you scream." He pursed his mouth into a thoughtful moue. "It's not quite the same as having a visual, but I can make do."
He turned and strode out of the library. Castiel struggled against his bonds, only to lose his breath as fiery pain erupted through every nerve ending. He lay on the floor panting for a long moment before it calmed. Maybe Sam and Dean would come to their senses soon and realize they had no choice but to kill Lucifer—kill them both.
Yet, deep down, Castiel knew they would try everything else first. And the longer they let Lucifer live, the greater risk the Devil would end up manipulating them.
No, Castiel couldn't let that happen. Which meant he had to figure out a way to destroy Lucifer from the inside.
Oh, did you hear the rain?
Oh, the rain?
You can try and run and hide
Tearing at the chain
Oh, Lucifer's inside
"Cas!"
"Cast him out!"
"Fight, you son-of-a-bitch!"
"Here's a new proposition for you boys. Let us go, or I'll start torturing Castiel."
"Cas!"
"You know all the delicious fun I can have, don't you, Sam?"
"We will figure out a way to banish your sorry ass."
Castiel squeezed his eyes shut and tried to block out the voices. Whether Lucifer was intentionally letting him hear or not didn't matter. He had to concentrate, had to think…
The barbed chains burned where they dug into him, Lucifer's corrupted grace coiling around Castiel's like a snake constricting its next meal. Wait, Lucifer's grace… If Castiel could tap into it, he could then try using it against Lucifer.
He cautiously reached out to touch a strand woven into the chains. It seared his own grace at the contact, and Castiel had to bite down hard to keep from making a sound. Breathing sharply through his nose, he focused on absorbing more of that fetid energy into himself. It hurt worse than anything, but he ignored the pain and kept at it, going slowly so as not to draw attention, and to not overwhelm himself too soon. He needed this to work. Needed to channel enough grace so that he could burn them both out.
Oh, did I send a shiver
Down your spine?
Well I do it all the time
It's a little trick of mine
Did I make you shake your knees?
Did I make him spill his wine?
Dean felt sick to his stomach at the way Lucifer made Cas's face twist into a sneer. He kept shouting over the Devil's threats, trying to reach Cas again. But the spell that had suppressed Lucifer had fizzled out, and Sam was with Rowena trying to determine if they could try it again. They just needed more time to convince Cas to fight, because they sure as hell weren't going to kill him just to kill Lucifer too.
"Cas!"
"Cas!" Lucifer shouted back mockingly.
Dean reeled back.
Lucifer lolled a dry look at him. "Castiel can't hear you anymore, Dean. He doesn't want to. He doesn't even want to be saved. Never did."
Dean's throat constricted as those same words spoken by Sam echoed through his mind. "Yeah, well, he's not exactly thinking straight lately, is he?"
And that hurt just as much as finding out Cas had said yes to the Devil. Because how the hell had Cas gotten to a place where he was that suicidal…and Dean hadn't even noticed?
"I am not sacrificing Cas," he added, hoping his best friend could hear him.
Lucifer smirked. "Then I suggest you let me go."
Dean pivoted and stormed over to Sam and Rowena. "Anything?" he demanded.
Sam gave him a sympathetic yet worried look. "No. We won't be able to do that spell again."
"Is there a spell to evict Lucifer from this end?"
"I suppose I could try to come up with something," Rowena hedged.
"Try anything, and I'll kill Castiel before you have a chance to finish uttering a spell," Lucifer called out.
They snapped their gazes toward him where he wriggled in the chair with a grin.
"And then I'll have this vessel all to myself."
Dean's breath stole from his lungs.
Lord, I'm spreading like disease
Lord, I'm all up in your mind
Oh, Lucifer's inside
Lucifer's inside
Lucifer slipped into the deep recesses of his shared mind where he'd left Castiel. Let the Winchesters and the witch continue their pow-wow. They wouldn't come up with anything so quickly, and Lucifer still had an ear trained their direction. At the first sign of them trying to pull something, he'd make sure they regretted it.
But in the meantime, he had to ensure he wouldn't get any lip from the opposite end.
Castiel was still on the floor, shaking minutely as the barbed chains shredded his flesh. Lucifer crouched down next to him and put a deceptively gentle hand on the lesser angel's shoulder.
"Oh, dear brother. You know it pains me to do this to you." He tutted. "We had such a good arrangement before."
Castiel pried his bloodshot eyes open to glare at him.
"I know, I know," Lucifer went on. "It was only because you thought the Winchesters would come kill us in the end. Right? I gotta say, I'm just as surprised as you are that they're being so mule-headed about it. I mean, not sacrificing Sam, I totally get. But you? What are they hoping to achieve by getting you back? Broken and used up as you are, what good are you to them?"
Castiel closed his eyes and tried to turn away. Lucifer moved his hand up to cup the angel's neck, and squeezed.
"It's not like you didn't already know this, little brother." Lucifer leaned down to whisper in his ear. "I see your mind. Every dark little secret. How much you yearn to be loved, to be part of a family again. How you thought you might find that kind of belonging with the Winchesters. But you're just a tool to them. That's really what they're trying to get back."
Castiel didn't respond, and Lucifer smiled.
Oh, did you hear the rain?
Oh, the rain?
You can try and run and hide
Tearing at the chain
Means I'm coming home again
Means I'm coming home my friend
Castiel shuddered under Lucifer's touch. The words seeped into him like poison, but it wasn't anything he hadn't heard before. Perhaps that was why Lucifer chose them. The proverbial nail in the coffin. Years' worth of emotions long bottled up threatened to overwhelm him now, but Castiel fought to keep them at bay, fought to maintain his precarious concentration on siphoning off Lucifer's grace right under the Devil's nose.
And then a softer voice trickled through the far corners of his mind.
"Cas, please."
Dean rarely sounded so broken as he did now, voice cracking even in prayer.
"Don't do this. I- I can't… I need you. You're our brother, Cas, and I should have told you that a long time ago. Please, fight him. Come home."
"Aw, isn't that sweet," Lucifer clucked.
Castiel turned his head up to meet the Devil's eyes. "You don't see everything."
He unleashed the ball of grace he'd been collecting with explosive force that threw Lucifer across the room and smashing right through a concrete support pillar. The chains around Castiel began to crumble, and he struggled to get to his feet.
Lucifer shoved a slab of cement off as he, too, staggered upright. His eyes flared red. "Why you little—"
Castiel thrust his palm out, and an invisible force slammed into Lucifer's chest again. He hit the wall with a thunderous crack that branched up to the ceiling, shaking loose bits of silt and plaster.
Castiel moved forward, only to stumble as a wave of dizziness hit him. Lucifer was up in that split second and storming across the room. He grabbed Castiel by the front of his shirt and swung him around. Castiel went flying into a study table, splintering it beneath his weight.
Lucifer was on him again before he could recover, straddling his chest and raining down blow after blow. His cheekbone split, and the tang of copper splashed in his mouth. Castiel let himself fall limp and released the rest of the grace he'd harnessed, sending it coursing around the library in waves of molten fire.
Lucifer reared back, eyes blowing wide. "You'll destroy us both!"
Castiel lolled his gaze upward. "That was always the plan. Weren't you paying attention?"
Lucifer seethed at him, and drew his arm back to deliver another blow, but heat belched above their heads, making him flinch. With a raging roar, Lucifer launched himself into a torrent of swirling grace that burst through the ceiling in escape.
Castiel watched in dismay, hoping the Winchesters truly did have a means of sending the Devil back to the Cage. The fire spurred by Lucifer's grace in the library died with his exit, and Castiel dropped his head back against the floor as darkness crept in around the edges of his vision.
Oh, Lucifer's inside
Oh, Lucifer's inside
Oh, Lucifer's inside.
Sam watched in horror as Cas's body seized in the chains.
"What's happening?" Dean demanded.
"I don't know!" Rowena yelled back. "I didn't do anything!"
Dean whirled back to the chair. "Come on, Cas!"
Cas's head wrenched backward, and suddenly a stream of brilliant light shot out with the scream of a jet engine. A gale whipped up in the small dungeon, pushing Sam back a step.
"The spell!" Dean shouted, and Rowena scrambled back toward the table.
Sam threw an arm up to shield his face, barely able to hear Rowena shrieking the words that would send Lucifer back to the Cage. The torrent of grace twisted and writhed in the air, and Sam felt like his ear drums were about to burst. But then there was a whooshing sound, and the light was suddenly slurping toward a grate in the floor, sucked away in an instant that left a dead silence in the room save for Sam's blood roaring in his ears.
"Cas!" Dean's cry broke the stupor, and Sam jolted as his brother quickly thwacked a rag over the holy fire to put it out. Then he was hopping into the circle and grasping Cas's face, angling his lax head up.
Sam hurried over, heart pounding painfully behind his ribs. What if that storm of grace had been two angels, not one? Or what if it had been the wrong one?
Cas's eyelids fluttered open.
"Cas?" Dean called, voice on the edge of devastation.
Cas blinked at them, then slid his gaze around the room. "Wh- where's Lucifer?" he asked hoarsely.
"Back in the Cage," Sam breathed, though he cast a questioning look over his shoulder for confirmation.
Rowena nodded.
He turned back to Cas. "Are you okay?"
The angel's brow furrowed. "I'm…still alive," he said disbelievingly.
"Yeah, you held on," Dean replied with a relieved smile.
Sam was still edgy, though, wondering if Lucifer was trying to trick them.
Dean clapped Cas on the shoulder. "Good job, man."
He turned away to grab the key for the chains, and that's when Sam saw it, the way Cas's expression crumpled with disappointment. And Sam knew.
He hadn't fought to come back.
He hadn't expected to be saved.
Sam found himself just standing there as Dean got Cas out of the chains and helped him to his feet. Cas staggered against him, obviously weakened, and Dean made a comment about getting him to a bed for some rest, as he'd been through Hell these past several months.
"Sam."
Sam blinked, swallowing hard.
Dean shot him a peeved look. "A little help here?"
Sam quickly slipped Cas's other arm over his shoulder to help support his weight as they carried him out of the dungeon. Cas didn't say much of anything, and there was a heaviness to him that spoke of more than just physical exhaustion. Sam couldn't tell if Dean noticed or not.
They got him into a bed and Dean made rambling comments about getting some rest, and did he want any soup. Cas's responses were monosyllabic at best.
Sam's chest tightened. He'd suspected—known—since the day he found out Cas had said yes, that this had been a suicide play. And Lucifer had a way with messing with one's head, making things worse. Sam knew that intimately well. And it filled him with dread.
Because Lucifer may be gone now, but his whispers would still linger and fester, deep down where it was hardest to reach in and cut them out.
Sam was afraid they still had a devil to fight, and it was a battle that was going to take everything they had.