After the apocalypse, Dean walks the remains of the Earth. He's alone, except for Lucifer…and maybe Sam. (Not "In the End" verse, but breaks from canon right before that episode in season 5)

If anyone's reading this, I figured I should ask for feedback about what you want to read. Send me a request, if you like, or tell me if you would you prefer:

1. Castiel gets to the bunker a minute too late, and the angel is left trying to hold the Winchesters together in the aftermath of demon Dean's attack on Sam. (NOT a death-fic)

Or

2. When a freak hunting accident leaves 17 year old Dean brain-dead, John makes a deal, and the timeline of the apocalypse is pushed up a bit.

And Walking Up and Down It

After the world ended, Dean watched the remains crumble around him. It was all very predictable, really: all the buildings that hadn't been destroyed in the Lucifer-Michael final showdown fell in the tearing hurricanes and twisters that followed. Food became harder to find. Disease ran rampart. Demons overran the earth, picking off the humans who haven't picked off each other until one day they all disappeared, leaving behind their meat suits as worn out, lifeless husks.

Dean's friends were already dead, at this point. Jo and Ellen and Bobby and Chuck and last of all Cas. He fell in with others, just to not be alone, but his little band of survivors saw a lot of turnover and eventually he finds that no matter how far and long he walks he can't find any other human. So he does the sensible thing: he takes his last still-working gun and blows his brains out.

And then wakes up, with a light dusting of blood and brain matter on his clothes and the Devil in his little brother's skin standing over him.

"It was one of Sam's conditions, when he said yes. That I not allow you to get hurt." Lucifer explains, inclining his head in a half-shrug, a mannerism he stole from Sam. "Or Bobby Singer, or the angel Castiel, or Ellen and Jo Harvelle, among others. Of course, he had no way of knowing that you were the only one on his list who was still alive."

Dean sits up, feeling his skull. He contemplates screaming and cursing and stabbing and shooting, but figures there's really no point in wasting the energy. "Can Sam hear me?" he finally asks, and Lucifer shakes Sam's head.

"I've put his consciousness away in a comfortable place in his head, for now. I didn't want him to have to watch this."

"What?" Dean snarls. "The end of the world? He fucking ended it, why shouldn't he have to fucking watch!"

Lucifer says nothing, eyeing Dean with vague curiosity.

"Why?" Dean finds himself demanding. "Why did he say yes?"

"Why do you want to know?" Lucifer says. "How will that information help you? Do you want me to say I tortured him? Of course I wouldn't do that. That I tricked him? I didn't."

Dean doesn't want to admit how much that knowledge fucking hurts. "Let me talk to Sam."

"You don't understand Dean," Lucifer sighs. "And I'm not going to let you talk to him. Not yet." He disappears with gentle wingbeats, like Cas used to do, an eternity ago.

So, the last human in the no-longer-the-world and with no end in sight, Dean wanders.

Dean's aged decades in the years since the apocalypse started. His knees ache all the time now, and he knows from glimpses of his reflection in pools of water that there are deep lines around his eyes, and his hair is edged with gray. Lucifer, in contrast, has kept Sam in pristine condition. Sam is young and fit and dressed in the most fucking stupid bright white suit, and will be like that forever. Sometimes Dean wonders if Lucifer's "don't allow harm to come to Dean" rule covers his natural death of old age, if he'll just keep getting older and older, shrinking and withering away while Lucifer keeps him alive.

Sometimes Dean happens upon pieces of wrong-colored fruit as he walks, or a loaf of soft fluffy bread sitting on a mound of rubble. And sometimes he eats them, just because he misses eating, and sometimes he doesn't, just to spite Lucifer's gifts. Dean hasn't bothered asking the archangel why his rib sigils no longer work—he suspects it's because Cas is dead.

Lucifer is rebuilding the Earth, on his own terms. He does it incredibly slowly, exploring possibilities in one tiny pocket of the planet at a time, but hey, he has the time. It's not like his one true vessel is going to be burning out on him any time soon. Or ever.

Often, he pops up wherever Dean is to do his experiments, and Dean watches as the archangel creates shimmering waterfalls that tumble down from nowhere and towering crystalline mountains and trees with broad red leaves. Part of Dean is disgusted with himself for hanging around and watching Lucifer play with the remains of the planet, and part of him can't help but be fascinated, and wonders exactly what Satan is going for, and is so fucking alone.

Once, as he treks through what used to be Florida, he finds Lucifer on a gray shoreline, reimaging the tidal ecosystem. Dean examines his efforts with a dull interest. As he stares at Lucifer's new take on fish—jewel-colored boxlike creatures with long spindly arms that stick out of the water, catching the light and waving in not unfriendly ways—a thought occurs to him.

"The angels said it would be hell on Earth."

Lucifer frowns. "Excuse me?"

Dean picks up a rock from a tidal pool. It's pale red and seems to be lit with a warm internal glow. "If you got out of the Cage. If you won. Cas said that it would be literally hell on Earth."

"They were just trying to scare you." Lucifer wanders over to the edge of the water, staring out over the gentle waves. "Why would I want hell on Earth, Dean? Hell was my prison just as much as it was yours."

Dean snorts. "I doubt that."

"As you doubt everything that I say."

"Yeah, I wonder why that is."

Lucifer's lips quirk. They stand in silence for several minutes. Eventually Dean speaks, pitching the rock into the water.

"My advice? Ditch the glowing shit."

"Too showy?"

"Yeah."

Lucifer nods thoughtfully, and for a moment Dean can forget the stilted speech and the stiff way he holds his shoulders and everything else and imagine that he's Sam. That Dean is helping his little brother with a school project that Sam is way, way too invested in, given that they'll probably be skipping town before he gets the grade back.

Right. Design your own post-apocalyptic hellscape. Destruction and desolation required. Humanity optional.

"I want to talk to Sam."

Lucifer shakes his head. "Not yet."

He catches sight of Lucifer's inventions almost every day, now. A massive, growling, lumpy creature that looks like a cross between a hellhound and a sabertooth tiger with shining gas-flame blue eyes. A group of twenty foot tall mushrooms that glow gently purple and green in the darkness. Dean remembers someone (Sam) once telling him that before trees, the Earth was covered in giant mushrooms. He wonders if Lucifer is revisiting God's greatest hits in some twisted homage to his distant Dad. Or a straightforward screw-you.

Dean wouldn't mind seeing a T-rex sometime.

He walks into the sunset for a month, and eventually reaches somewhere hotter and drier. He finds a cheeseburger with extra onions lying on the side of a busted up road, and feeds it to six-foot furry dragonfly that bumbles past.

A mile down the not-road, Lucifer is waiting for him. He's summoned a small clump of clouds and made them spew a fine mist of pinkish rain that smells overwhelmingly of peppermint. The Devil is looking at Dean expectantly. He wants Dean's opinion.

"Why are you following me?" Dean screams at the archangel. "Why the fuck can't you just leave me alone?!"

Lucifer's face is suddenly cold and furious and unfamiliar. "Sam loves you. I wanted to know why."

"You know what I think?" Dean says the next time Lucifer finds him, this time with a small, scaly frog-fish that scurries away on creepy fin-hands when Dean lobs a rock at it. "I think you burned Sam out a while ago. I think he's gone, and you're lying to me."

Lucifer blinks at him, actually seeming to be surprised. Dean hopes desperately and is terrified that he's right, and that Sam is gone.

"Sam is still in here, Dean. I could never do that to him. I don't feel complete without him."

Dean hates this the most. When Lucifer talks about Sam like he loves him. Like Dean's little brother is soulmates with the devil.

"Then let me talk to him."

"No."

"Why the hell not? What do you think I'm going to do?"

"Sam is not ready for that. You are not, either. It would only end in more pain."

Deans laughs at that, hearing the hysteria in his voice and not caring. After all the deaths and the destruction and the end of human civilization, how can there possibly be more pain?

"You said Sam loves me? That's why you keep following me around?" Lucifer tilts his head in acknowledgement. "Well, you can go ahead and tell him that I don't love him. Not anymore. Not after everything he's done."

Lucifer narrows his eyes. "Dean."

"No. I don't. I fucking don't. He ended the fucking world. Everyone is dead. Why the fuck would I still love him?"

"You don't mean that, Dean," Lucifer says. His voice is icy, his eyes even colder.

"Yes, I do," Dean says, and he does, and he hates that, and he doesn't, and he hates that too. His world is nothing but hate. Hate and Lucifer's acid-trip landscapes.

"I see," Lucifer says, and flies away.

He reaches what must be the Pacific Ocean, and can't help but think that it's a little closer to the Atlantic than it used to be. Did Lucifer just peel away California and throw it out into space? Stanford was in California.

There's something in the water, something the size of skyscraper and appears gold-plated as it breaks the glassy surface. It makes the only movement in the water that Dean can see for miles. Apparently Lucifer has rethought the tides.

A shadow falls over him and he doesn't look up. Lucifer settles beside him, dangling Sam's legs over the cliff Dean's sitting on.

"I want to show you something," Lucifer says.

Dean is about to say, no shit, that's all you've been doing for who the fuck knows how long, you know you killed your big brother, right, and you don't get to replace him with me, and then the archangel adds: "No, that's not right. Sam wants to show you something."

Dean doesn't struggle as Lucifer places a hand on his shoulder and this time, they both disappear.

They reappear, somewhere with flat, rubble-strewn earth and a low-hanging haze and it looks like everywhere else Dean's been, except it doesn't. There are none of Lucifer's little side projects, he realizes. It's an all-natural post-apocalyptic hellscape.

"What?" Dean asks. "What does he want me to see here?"

"Not there," Lucifer says. "Behind you."

Dean turns, and his brain can't quite process what he's seeing. The ground suddenly feels uneven beneath his feet, and the sky tilts, because he's not looking at vast empty expanse of broken buildings and deadness.

There are people, a few hundred yards away. There are humans close enough that if Dean screamed, they'd hear him. There's a whole crowd of fucking people and Dean's not alone anymore.

The reality of what is happening hits Dean full in the face and sinks into his stomach. He's going to tell stories and have new stories told to him. He's going to play poker again. He's going to have sex. He's going to have a conservation with someone who isn't the fucking devil. Tears are soon blurring Dean's vision of what he's pretty sure is the last miracle that will ever take place on Earth.

"Why…?"

Lucifer shrugs. He's looking at the humans (the fucking humans; there are other people besides Dean) with distaste etched on Sam's features, like they're a nasty cockroach infestation. But he's not killing them.

"Sam didn't want all of the humans to die. He wanted me to give them a chance to prove themselves. It was important to him."

The people (fucking people) are milling about, picking over the field. But they're not just scavenging, Dean realizes. They're moving in an orderly fashion, walking in parallel lines, bending over every few steps. They're planting crops. They're trying to grow their own food, make the land green again.

"How many?" Dean manages to croak out.

Lucifer shrugs again. "Enough."

Dean doesn't know if "enough" means enough to make Sam happy, or enough for their very presence to disgust Lucifer, or enough for humanity to start over and reclaim the world. He doesn't care.

"Let me talk to Sam," comes out of Dean's mouth.

"What are you going to say to him?"

Dean's thought of a million things he could say to Sam since Satan claimed his vessel and cities started being blown off the map.

You're fucking dead to me, you understand that, Sam? had darkened his thoughts more than a few times.

I'm going to spend the rest of my life finding out how to kill you. Not him, you, burned in his mind when he came across the charred remains of a teddy bear in what used to be Lawrence.

I should have listened to Dad and taken you out when I had the chance, when he made the painful mistake of thinking that far into the past.

I understand why you did what you did, although that was a lie.

I fucking hate you for making me miss you after everything you've done.

I'm sorry that I left you alone. I know it hurts so fucking much to be alone.

Thank you for saving at least some of them. It was more than I could do.

"I don't know," Dean answers, because he realizes he doesn't. He's pretty sure he'll have no idea what to say until he's seeing Sam looking out of Sam's eyes.

"Not good enough," Lucifer says, shaking his head. "But you'll have time to think about it."

Lucifer disappears, taking Sam with him, and leaves Dean with what's left of the world.