Sam had been on the cusp of becoming a lawyer, Dean thought; he ought to have seen the obvious loophole.

The entire world dying slowly and by inches, and Sam, stupid fucking Sam, got one wish from the devil, one favor once he was cornered into saying yes, and he said don't let Dean die. Please don't let him die.

Lucifer, as he had smugly informed Dean from Sam's mouth as Dean was standing in the middle of the blast radius that had been Kansas City, always kept his promises. Dean was holding an empty gun at the time and trembling, staring his brother (not his brother) in the face. Sam/Lucifer smiled at him. "Take care, Dean," he'd said, and gone in a flutter of wings.

One thing you could say for Lucifer. He wasn't unnecessarily slow. Once he got settled inside Sam's skin, people died by the thousands, hundred-thousands, daily. Cities wiped off the map altogether. When New York crashed, burning, into the sea, and Dean's frantic screams for Michael went unanswered, he gave up. Nestled the muzzle of a gun under his chin and pulled the trigger.

And that was when he found the loophole.

Don't let Dean die, Sam had asked. Desperate, out of options, with his brother's life on the line (always their weakness) and Lucifer had taken that request at its very face value.

Dean got to watch the world end. Lucky him.

~.~

People, Dean realized, were a lot like cockroaches. You took your eyes off them for a minute and they started breeding and multiplying and pretty soon you had to call the exterminator.

Lucifer had other continents to decimate. In the meantime, people tried to pick up and rebuild. They never got very far.

At first, Dean tried to work out some way to stop it. For a little while. That got nowhere. Then he tried to find a way to get out. That didn't work either.

It was almost funny, though, the time he provoked a demon into attacking him, the look on its vessel's face before it simply…combusted. (If he didn't have black humor, he wouldn't have anything at all.)

Every few years, Lucifer turned up, apparently just to talk. Dean would be sitting on a rock in the middle of a wasteland, or under a tree, or sleeping in the shell of someone's house and open his eyes and there would be Sam, leaning against the wall. Thankfully no white suit. Just jeans and Sam's old jacket, the same as it'd been the day he surrendered.

Dean suspected the devil got bored.

"All cities are ugly," Lucifer might opine, "But honestly, Chicago? Particularly terrible."

Or: "Bored, Dean-o? I could send a few demons after you if you want. I don't have any use for them at this point."

Or, once: "Sam misses you. Even…asleep, as he is," which made Dean both want to scream and punch something and shoot something, possibly all at the same time. He went with punching and nearly broke his knuckles. Lucifer seemed faintly amused.

"You are a surprise, Dean," he said. "Not what I would have expected. It's…refreshing."

"You're exactly what I expected," Dean snarled back. Lucifer had the fucking nerve to laugh.

~.~

The first time he walked into a village (town would be too generous) and they got suspicious, they shot him on sight. There just wasn't time, at this point, to wait and find out if the new kid on the block was a demon or not. You'd be dead by the time they were inside.

Which was the first time Dean failed to die in front of anyone else.

It turned out that didn't go over so well. He woke up strapped down with a gun leveled at his face. They promptly tried the usual suspects – silver-salt-iron – and Dean groaned and said, "It won't work."

They shot him again. That really hurt.

When he came back that time, they just looked pissed. "Look," Dean tried. "I'm not evil. I just can't die. It's actually kind of a pain in the ass."

When he came around again, there was nothing left of the house he'd been sitting in. He still had the chair, but the bonds were gone. Scattered like dolls around were bodies, broken and half burned.

Lucifer was standing a couple feet away, leaning against some rubble with his legs stretched out, one foot pushing a corpse back and forth. He smiled at Dean. Easy and almost sympathetic. "Sorry about that," he said. "I was busy, took me a while to get here."

"You didn't have to stir yourself on my account," Dean said, dryly. His stomach was churning. He could hear someone making desperate, choked, whimpers somewhere. Lucifer seemed amused.

"It was no trouble," he said, modestly. "Humans. They never give up, do they? It would be almost admirable if it weren't so irritating."

Dean didn't bother to respond to that. Lucifer rubbed his nose in a way Sam never would have, looking thoughtful. "The other day," the Devil went on, "I found a group of them trying to make a sacrifice to me. Human sacrifice. They're disgusting creatures, Dean, really. I don't understand the appeal."

Dean felt his lip curl. "You didn't like that?"

Lucifer snorted. "I don't have any use for sycophants. Or any human. They're all equally abhorrent to me. Nor am I particularly fond of treachery."

"What do you call what you did?" Dean asked, wondering vaguely if he was suicidal before remembering that, oh yeah, Lucifer kept his fucking promises. Maybe if he could piss the devil off enough he could change his mind. End this farce.

Lucifer cast him a sharp look, more peeved than angry. "Rebellion, Dean. You should know how different the two are." For a moment, he looked almost pitying. "I almost wish I could have destroyed all of humanity then. In the long run I think it would have saved everyone a lot of trouble, hm?" Dean just stared at him, and Lucifer shrugged. "None of them seem particularly happy," he said, casually. "All of them wriggling around on the surface of this planet, suffering and puking and dying a little at a time. Gleefully slaughtering each other for the slightest reason. Don't you think it's time someone put them out of their misery?"

"And that's you?" Dean said. The crying had faded. Lucifer smiled, bright, Sam's dimples marking his cheeks.

"What can I say," he said, spreading his hands. "I'm an altruist."

~.~

Dean spent the first four years hating Sam for giving in. In the end, though, it just wasn't worth it. Sam was gone. He wasn't coming back. There wasn't any real point.

Wasn't much of a point in anything.

Lucifer did what he wanted. Dean couldn't die. He didn't need to eat and didn't get sick with any of the nasty things making a resurgence. Nothing much changed. Lucifer still periodically turned up and reported on the state of things.

Dean's sleep was dreamless as it hadn't been for years.

Six years in when he came upon a small collective of people, scrawny and half-dead in the middle of nowhere, they didn't shoot him. Looked at him with something like awe, and then fell to the ground, kneeling with their faces in the mud.

Dean blinked at them.

They didn't speak, though Dean thought it was more out of terror than lack of ability. They pressed a loaf of moldy bread into his hands, fluttered in nervous circles, simultaneously terrified and worshipful. Dean didn't know what to do. Hardly even remembered how to interact with people in normal situations, and this was assuredly anything but normal.

It occurred to him that Lucifer would probably follow him here and he should leave before he got this little knot of people killed.

It occurred to him that it didn't really matter; they probably wouldn't last long anyway. (Probably he should have felt bad about how bleak that thought was. He didn't. Really.)

"Um," Dean tried, voice rusty from disuse. "What do you want from me?"

They stared at him blankly, like they didn't understand what he was trying to say. Their eyes were blank and dull, like they were dead already. Finally, one of them, probably the oldest one, lowered his eyes and said, "Please. You will go?"

Dean hadn't expected that. Didn't know what he had, but it wasn't that. "What?"

"We know you," said the man, who seemed to be speaking for the group. "You are – the devil follows you. You are the angel of death. We respect…only please. We have given you what we have. Pass over us. We have suffered enough."

It was only the voicing of what he'd thought a moment before. Dean still felt abruptly like he was going to throw up. Angel of death. Sounds about right. Everyone you've ever loved- He took a quick step back of his own, holding up both his hands. "Yeah," he said, quickly. "Yeah. Okay. I'll go. I…you'll be fine."

One of the girls, probably about twelve, started crying. Turned and hid her face in her mother's skirt. "Thank you," the woman whispered. "Thank you."

Worst lie he'd ever told. He could taste it in his mouth, sour like bile, copper like blood. He turned his back and walked away before he could do any more damage. Didn't look back until he was sure he couldn't see them, or their house.

Passing by was probably enough to doom them. A couple days, and they'd be gone too. Angel of death.

And this was the world he got to live to see.

~.~

He wandered into a town that looked like it hadn't been touched except for the fact that it was completely empty. There was a diner on Main Street and when Dean walked in Sam was sitting at one of the empty booths.

Sam raised his eyebrows. "There you are," he said. "Took you long enough," and his tone was so pitch perfect that for a moment Dean almost thought the whole thing had been one mad, fucked up angel power trip. Just a moment.

Dean crossed the diner and sat down across from Lucifer. "You're not fooling anyone," Dean said.

"You know," Lucifer said, "I thought about letting you talk to Sam. I'm glad I didn't do that. Did you know they've given you a name?"

"Who," Dean asked, flatly, and Lucifer looked at him almost pityingly.

"The humans," he said. "They call you a few different things. Samael, funnily enough, seems to be one of the most popular. Known to you as one of the various angels of death. They leave out offerings of food and treasures in front of their hovels, hoping that you will favor them and protect them from me." Lucifer seemed amused. "Honestly, it just makes them more conspicuous."

"You say 'humans' like you forget I'm one of them," Dean said, flatly. Lucifer quirked an eyebrow at him, another one of those expression so perfectly Sam, and Dean wondered which way it went, if Sam had always been a little like Lucifer or Lucifer was becoming a little like Sam.

"Are you?" Lucifer murmured. "What makes a human, Dean? You're not mortal anymore." He leaned his elbows on the table, propped Sam's chin on his hand.

"Yeah? What am I supposed to be, then?" Dean snapped, feeling his spine crawl, and Lucifer laughed.

"Well," he said. "That's an existential question, isn't it?" He looked around the diner. "Sam would like this place. It used to be like home, these kinds of towns, am I right? Perhaps, for that reason, I'll let this one stand."

"What do you need me here for?" Dean asked, "Do you get lonely?" and Lucifer looked at him for a moment.

"A continual quest," the devil said, finally, "To work out what your brother sees in you. I begin to think I may even like you. You are, at the very least, entertaining."

"Well," Dean said. "That's just great."

"I wonder how long it'll take you, Dean," Lucifer murmured, "To realize that this is what the world was coming to all along. You know it, I think, deep down."

"I think the human race as a whole would rather suffer than die," Dean said, and Lucifer raised an eyebrow at him.

"Really? So you've never wanted to just be done, Dean? Never wanted to lay everything down and give in to the evil you saw devouring the world?"

I'm just…tired, Dean thought, and closed his mouth.

"I thought so," Lucifer said. He stood up. "You can, now, you know. Set it all down and just be whatever you want to be. Just think about it, Dean. I'll see you soon." He smiled, a brief flash of Sam's dimples making Dean's heart squeeze. "I'll give your love to Sam."

~.~

Dean had been unable to die (the world had been ending) for twenty years. There was a forest growing in the ruins of Seattle. He hadn't seen another human being for five. Dean kind of figured they were probably all dead, finally.

Just him. Just Lucifer, circling like a vulture. Never there long, never gone long.

"Going on a visit to Asia," he would say, idly. "I'll be away a bit."

It was a slow, sinking feeling the day Dean realized he missed the company. That he'd forgotten to think of Lucifer as the devil. As evil. He sat down and tried to think of the things he missed about the old world, and couldn't remember anything.

Except for the car. He did miss the car. Even if it all did seem impossibly far away; another life and further.

He walked to the sea and looked out at the waves, crashing and crashing and crashing, rolling out and in.

"What do you think, Dean?" Lucifer asked, suddenly standing beside him. Dean hadn't even heard the sound of wings.

The sea was a stormy gray and the clouds hung low in the sky, heavy with rain. Seabirds were skimming low over the surface, cries high and thin. He could see clear out to the flat horizon. "It's beautiful," he said, quietly.

"Strip away everything else," Lucifer said, "And beauty's all that's left. The world as it should be."

Dean looked at Lucifer standing beside him in Sam's skin, more comfortable there than Sam had ever been. Relaxed, a small smile turning up the corners of his mouth as he looked out at the sea.

Lucifer turned his head and met Dean's gaze. "You understand now," he said, not really a question. Dean nodded, once. "This was always how it was going to be. Sooner or later, it comes down to this." He tilted his head back. "I'm glad you never said yes to Michael, Dean. It gave me the chance to get to know you."

Dean nodded, barely, in acknowledgment. Lucifer's smile grew, and he turned the rest of the way, leaned down and pressed a light kiss against Dean's forehead, then his lips, perfectly chaste.

"See you soon, Dean," he said, and was gone, in a flutter of wings.