Author's note: hehehehhhh it's been ages, I know, I'm sorry. It has also been brought to my attention that Zachariah is not traditionally considered an archangel, but for some reason I decided that he was in this fic and I'm sticking to it. Also there is sudden gruesome imagery in this chapter. That's all. Enjoy!

Dean heard the sound of feet slapping concrete, and then his brother and Cas were leaning over him.

"Dean?" Sam asked, at the same moment that Cas said, "Lucifer, what happened?" Sam glared at Cas, then at Dean.

"S'me, Sammy," Dean groaned, trying to catch his breath. He managed to struggle into a sitting position, then vomited. He could feel Lucifer, trapped behind whatever spell Gabriel had cast, and the archangel was deadly silent. Dean could sense his cold wrath growing, Grace like ice where it bordered Dean's soul. The sensation was uncomfortable, terrifying even, and Dean almost threw up again. Instead, he braced his hands on the floor and took deep breaths, trying to control his shaking body.

Lucifer? he asked hesitantly, reaching out a mental hand to the archangel. Lucifer's Grace surged against its bonds, suddenly wild and furious, and part of it slipped past the wall and twisted Dean's thought until the hunter let out a gasp of pain.

Do not speak to me. The thought was like frost creeping through Dean's veins, death by hypothermia. Dean cried out and pulled away. Gabriel's wall, already frozen, cracked a little. Suddenly, Dean became aware of Sam at his side, shaking Dean's shoulder.

"What is it, Dean? What's happening? Where's the devil?"

"Stop it, Sam!" Dean shook his brother off and got unsteadily to his feet, wiping his hand over the back of his mouth. Gabriel had said he would have a minute. How much time was left? Where was Dean even supposed to go? Another angry stab of ice from the archangel made him stumble. Anywhere, Dean decided. Anywhere but where Sam and Cas were. The archangel inside his mind was almost a completely different person from the sad, clever angel that Dean had said yes to. This was Lucifer the Fallen now, as clearly as if a switch had been thrown. Dean didn't want this angel anywhere near his family.

"Cas, take Sam to Bobby's. Angel-proof the place, and you either stay in there with them or run, you hear me? Don't come back here." Lucifer's murderous intent washed against the wall in Dean's head, and he shivered again as the cracks spread. "Don't come back for me, Cas."

"Dean, what the hell's going on? You really said yes? Who was that other angel?" Sam's voice was full of confusion and betrayal, and Dean flinched. he couldn't look at Sam, afraid that his brother might see the devil in his eyes. He wanted to tell Sam everything, but there was no time.

"Sam, I promise I'll explain everything later if I can. Cas can tell you most of it. But you two have to go now. I don't know when whatever Gabriel did is going to wear off, and—" Dean choked on his words as Lucifer tested his prison bars again. "Just go, Sam. Cas, take him!"

"Other angels will be here any moment, Dean. Let me take you with us; perhaps we could put you in the panic room—"

"That room's not designed to hold an archangel, and you know it," Dean interrupted, shaking his head impatiently. "Go. We'll be fine." Dean gritted his teeth as Lucifer stirred again, washing against the back of his mind like a pool of liquid nitrogen. He wavered, and this time it was Cas who steadied him.

"What is my brother doing?" Cas asked softly, face tight with concern that Dean didn't think was entirely for him.

"He's just—he wants to hurt them. He wants to kill all of them."

After a long moment's hesitation, Cas murmured, "you can force him out, you know. Just rescind your invitation, and he'll have to leave."

Startled, Dean just gaped at Cas. The option hadn't even crossed his mind, but... He realized that the archangel in his head, though still furious, had gone very quiet all of a sudden. Everything seemed to freeze. Could he really do that to Lucifer? Send him back to Hell? It might possibly save lives, angelic lives. Once more Dean was struck with the thought that he couldn't knowingly send anyone to hell, even Lucifer. But if Lucifer hurt Sam, or Cas...

"I—"

Dean wasn't sure what he had been about to say, but he was cut off by a terrible rushing sound and then several things happened at once. Angels landed all around them, blades drawn and ready to fight, Cas grabbed Sam's arm and reached for Dean, the last of Gabriel's power vanished abruptly, and the full force of Lucifer's rage fell on Dean. He screamed in agony, body convulsing and vision whiting out. The last thing he saw was Cas wrenching his hand back as though he had been burned.

}{

Dean floundered, blind and alone, in some dark corner of his own mind. Cut off from his body, he didn't even know how long he had been there. Then a light appeared, bright and horrible, and Dean would have run and hidden if there was anywhere for him to go.

"Dean Winchester." Lucifer's voice was terrible, devoid of any emotion save for a wrath that eclipsed Dean's very being. "How dare you?" Dean still couldn't feel anything but that overwhelming fury, as though he were naked in the middle of a blizzard.

"Lucifer, please," he gasped, but the archangel ignored him. The glare only grew, deadly sunlight reflecting off a glacier, searing Dean's soul.

"Did you think that was an acceptable trade, Dean? Your brother for mine? A human for the best archangel?" Lucifer continued to speak in that empty voice, every word a spear of ice through Dean's heart.

"I'm sorry," Dean mumbled through numb lips. "I didn't have a choice. Gabriel pushed me away. They were going to kill us both."

"Then we should have died!" Lucifer screamed, and true vessel or not the fallen angel's voice tore into Dean and left him bleeding. "You should have fought him! Instead, you abandoned him, forced me to abandon him!"

"He wanted us to go, Lucifer!" Dean didn't know where this strength was coming from, but he managed to hold together in the face of the archangel's power, resisting the frozen Grace that was trying to rip him to shreds. "He was saving you!"

"I should not have been saved!" In an instant, Lucifer's rage diminished, turning inwards. The gleam of his power dimmed, soot clouding the once pristine Grace. "Not for me. Gabriel should not have been sacrificed for my sake." And this, now this Dean understood. Tentatively, still terrified, he reached out towards the archangel.

"Little brothers do things like that, though. Whether we deserve it or not."

"How would you know?" The rage was back, clawing at Dean, but he held on, throwing his words at the fallen angel.

"You feel like he's so much better than you, and you don't deserve to have him care about you because all you ever do is screw him up when he gets close to you! You wish he'd just left you alone and gotten on with his life, because then he might have actually had one!" Lucifer's wrath melted away like an ice cube in the sun, and Dean finished softly, "I know, Lucifer. I'm sorry."

Dean's words were met with thick, smothering silence, and he wavered, drained by the assault of Grace that he had somehow survived.

"Gabriel is gone." Lucifer spoke slowly, as though testing the words to see how they sounded. "Dead. Or captured, to be 'reeducated'. Either way, my brother is truly gone this time." Sorrow came rushing up to fill the void left by Lucifer's anger, a sadness so deep and dark that it overwhelmed Dean. Exhausted and battered by their argument, Dean couldn't fight anymore, and he lost consciousness.

}{

Castiel flew Sam to Bobby's, hardly saying a word to the old hunter when he appeared in the center of the man's living room holding a battered Sam. "Apply the sigils. I will be back," he informed Sam tersely, already calculating what might have been happening to Dean in the seconds he'd been gone.

"Wait, no, Cas!" The hunter grabbed his arm, and Cas stared up at him, startled. Sam was not usually willing to touch him, even casually. "You can't just… just leave me here! What the hell is going on? Who was that other angel? At the end, was that Dean, or Lucifer?"

Bobby choked on whatever he'd been about to say, and Sam gave him a quick glance that Castiel interpreted as an "I'll fill you in as soon as I can" look. While he was distracted, Castiel carefully but firmly removed his arm from Sam's grasp.

"The other angel was Gabriel. I believe you know him as the Trickster. I promise I will tell you everything later, but right now I must go help them." If they were even still alive. If there even was a "them", and Lucifer hadn't harmed Dean, by accident or on purpose.

Castiel clenched his right hand into a fist and felt a sharp prickle in his fingertips as his Grace tried to heal the frostbite there. It was unnatural, of course, from an unnatural cold, and his vessel would not heal from it so easily. But Castiel had to believe that Lucifer had not meant to injure him, that he would not injure Dean, and that he would not come after Sam. The uncontrolled rage that Castiel had sensed just before he fled, though... and Dean had told him not to come back. But there was no way that one unarmed angel, even an archangel, even Lucifer, could fight the number of angels that Castiel was sure were coming after them. And even if he could… Sam's voice startled him out of his thoughts.

"Help them? Cas, you have to—"

"No, Sam!" Castiel's voice was rough. How long had he been here, now? Two minutes? Three? He needed to get back to Dean and Lucifer. "Put up the sigils. I will return when I can, with Dean. Do not leave the house." At that he was gone, tearing through space until he landed with a rush in the warehouse again, blade at the ready.

When he landed, the building was eerily silent and pitch black, doors closed and lights off or burned out. Castiel stood for a few seconds without moving, listening for the sound of other angels and letting his eyes pierce the darkness. What he saw, even though he had been half-expecting it, left him frozen with horror.

The first of the bodies, if they could even be called that anymore, lay only a foot or so away. Emael's head had been twisted nearly off his shoulders, clusters of ice crystals exploding from his eyes, his mouth, his nose. The corpse was on its stomach, Castiel thought, but most of the back, where his wings might have been, was scooped away, leaving the splintered ends of spine and scapula glistening and bloody. From so close, Castiel could see the inside of the vessel's ribcage, shattered from being thrown across the room. Charred black wings spread from the remains, and as Castiel followed them with his eyes he saw that the overlapped with another set of imprints, and another.

Slowly, Castiel's gaze tracked across the floor, counting with detached horror. Two more, five, nine, twenty. Two dozen mutilated bodies stretched out before him in a haphazard mess of death, and in the center of it all stood Lucifer, motionless, head bowed. Dean's clothes were soaked in blood, his skin stained crimson. Castiel took a careful step forward, but there was no reaction. He approached until he was only a few feet away, then hesitated. Dean's eyes were wide open but blank, as though there was neither man nor angel behind them. Castiel gripped his blade tighter to hide his shaking hands.

"Dean?"

No response.

"Lucifer?"

Dean's head whipped around, eyes so dark they might as well be black. In the space between heartbeats Lucifer vanished and reappeared behind Castiel, hands closing around the bases of his wings before Castiel realized what was happening. A searing pain shot through Castiel's body as Lucifer began to tear, the archangel's frigid Grace chewing through Castiel's physical and angelic flesh alike.

"Brother, no!" he shrieked, resisting the urge to thrash because struggling would only worsen the wounds. "It's Castiel; I want to help!" Lucifer stopped attacking, but remained silent, still gripping Castiel's wings tightly. "Lucifer?" Castiel twisted to look over his shoulder, panting slightly from fear. The archangel's eyes were completely insane, not a hint of awareness to be found. "Please, Lucifer," Castiel repeated softly, letting his blade fall to the ground. They stayed that way for another few seconds, a frozen tableau. Castiel knew that he was dead if he made one wrong move, so he made no move at all, waiting. Then Lucifer blinked, drawing in a shaking breath in a way that was so similar to Dean that Cas almost thought it was the hunter for a moment.

"Castiel?" Lucifer dropped his hands instantly, shame and fear written all over his face. "Did I—" he glanced around, seeming to notice all the dead for the first time. "No," he whispered, shock twisting his features. "I didn't mean to—I never wanted—"

"Lucifer." Castiel turned quickly and grabbed his brother's arm, sensing that he was about to bolt. "Wait. What happened?"

"I—" Lucifer glanced around wildly. "I killed them, all of them. All of the ones that came after me. I was just—Gabriel—"

Castiel shifted his grip to Lucifer's shoulders, shaking him slightly. "Calm down. Do you know what happened to Gabriel?" There was nothing Castiel could say about his fallen garrison right now, and he didn't even try.

"No." Lucifer's voice was tight. "I—Dean didn't see. He could be dead. Because of me. "

"It is not your fault," Castiel answered, as firmly as he could manage. "Listen to me. Gabriel agreed to help us knowing what might happen." Lucifer stared at him with Dean's hopeless green eyes, looking frighteningly small and lost, and Castiel swallowed hard. "We may still be able to save him. I do not think even Zachariah and Raphael would kill an archangel so lightly." Lucifer nodded slowly, and if he didn't exactly look hopeful, at least Castiel didn't think he would fly away as soon as he released him. Letting go and taking a small step back, Castiel asked his most troubling question.

"Is Dean all right?"

In a disturbingly uncharacteristic gesture, Lucifer broke eye contact, glancing down at the floor.

"Lucifer? What have you done?"

"Dean will be fine."

"Will be? Did you hurt him?"

Lucifer smirked humorlessly, glancing back up at Castiel with bitter eyes. "Look at us, brother. I fell because I had no love for humans, and you because you have too much. Your brothers and sisters lie slaughtered around you, and your concern is for one human soul?" The archangel shook his head, staring down at Dean's bloody hands in bemusement. "What is it about him, Castiel? Why does Dean Winchester inspire more loyalty and love in you than your own kind?" Glancing up and catching the look on Castiel's face, Lucifer added, "I was angry. I may have… damaged him. He will recover."

"Damaged him how?" Castiel demanded, resisting the urge to grab his brother and shake him. "Lucifer—"

"Peace, Castiel. Dean is all right. Exhausted, but surprisingly whole after weathering my wrath. I have not left him with any scars worse than those he already bears, nor any that will not heal, I promise you."

After another moment's intense scrutiny, Castiel nodded and stepped back. "Very well." Silence fell, one in which Castiel had time to truly consider their options at this point. Sam was safe for the moment, although it would be smartest for him and Bobby to relocate soon to avoid the retaliation of the angels. If Lucifer was not underestimating the damage he had caused, then Dean would be alright soon. If Raphael and Zachariah planned to reeducate Gabriel the way they had tried to "fix" Castiel, the archangel could probably resist for far longer than Castiel had. If they chose to simply kill him, though… sharp sorrow pierced Castiel's heart. In that case there was nothing Castiel could do anyway, so he refused to dwell on it.

"We need to leave, Lucifer. No doubt Raphael is already moving to try and trap you again. Let us return to Bobby Singer's house. We must relocate Dean's family, and they deserve an explanation from you and Dean as well."

Lucifer looked like he wanted to protest for a moment, but then his face softened. "Yes, they do. But first…" the archangel turned and stretched a hand out across the floor of the warehouse, over his fallen brethren, eyes drifting closed in concentration. A spark leapt from his fingertips, and an instant later a swath of flames followed, white hot and all-consuming. They washed over the floor, swallowing the corpses, searing the bloodstains away, and licking at the walls like an ocean of fire. Castiel flinched reflexively when they swirled around him, but the flames were cool and didn't even singe the tail of his coat. Lucifer saw the motion and smiled sadly.

"My fire burns only that which I want it to, brother. Do not fear. In fact, give me your hand." Puzzled, Castiel offered his left hand to Lucifer, but the archangel shook his head. "The one that I burned earlier."

Taking his brother's injured hand in both of his own, Lucifer focused on the frost-blackened fingertips. To Castiel, it seemed that this small act of healing took far more effort than setting the entire warehouse ablaze, but eventually a new flame blossomed out of Lucifer's palm. This flame was blue-green, and oddly warmer than the cleansing white fire of before had been. Mesmerized, Castiel watched the blackened skin of his vessel heal, the pain dwindle to nothing.

"Thank you," he murmured when Lucifer had finished, flexing his fingers. The burn in his Grace from Lucifer's previous assault had faded as well, although there was still a sort of spectral soreness around his shoulders.

"I am simply trying to clean up my own messes. The messes that I seem to constantly be making." Lucifer shrugged, and to Castiel's relief he cleaned the blood and gore from himself with the motion. "Lead on, Castiel. Take me to Dean's family."