Every demon is different, which is something that you'll have to keep in mind while hunting them. Each one is gonna have a unique skill set, things they've practiced for years and are really good at, just like people. But here's a general list of their abilities, just so that you at least know how to start preparing for a demon hunt:

Inhuman strength

Inhuman speed

Teleportation (range usually depends on strength of demon)

Telekinesis (varying range and precision

Inhuman reflexes

Possession

Empathy (yeah, they know what you're feeling)

Extreme resistance to psychological torture

Heightened senses (hearing, sight, touch, etc.)

Ability to communicate with other demons via pools of human blood

Don't think that this is a complete list. I've met demons who could control fire, read minds, levitate, hypnotize people with their eyes and voices…all sorts of dangerous stuff. So I guess the best advice I can give you is to expect the unexpected.

- Demons and Other Biblical Monsters, Sam Winchester

"Urnh!"

Droplets of blood splattered the floor and wall behind Sam's chair as he finally yanked one hand, his right, free of the zip tie that held his wrists to the back of it. He brought it up to his face and flexed, making sure it still worked, as he shook his other hand free of the now-loose makeshift handcuffs. Both of his hands were scraped raw and crimson from wrist to knuckles. They felt like he'd lit them on fire, but at least he could still use them.

Planting the heels on the edges of the chair, Sam forced himself up onto his feet with a grunt of pain and effort. And immediately found himself on the floor. He grabbed at his left leg, feeling his face screw up in agony. It wouldn't hold him. It hurt too bad, and he'd done too much with it; it wouldn't even stay straight. The muscles, usually knotted with cramping and scar tissue, felt like melting Jell-O under his hand.

He wasn't going to be able to walk. Not even if he went and got his cane. He needed crutches, and he didn't have any in the house. Which meant that he'd have to drag himself around, like he had after Dean had kicked him in the leg, to get everything that he was going to need. He was desperately short on time, but he didn't have any other choice.

Candles, herbs, a lighter, a spellbook. Retrieving all of it was an epic quest in and of itself, and left Sam's biceps trembling and burning. The floor had a lot of smeared, bloody handprints on it, too. It looked like a murder scene. He definitely felt like some sort of monster, dragging his lower body around like this. Teke Teke, but with his legs still attached, if useless.

He'd been able to use his right one at first, and half-crawling was much easier, but even it had never been particularly reliable, clipped by the wendigo and forced to do most of the work of the other for years. It cramped up fairly quickly, and then he had to drag it, too.

Into the demon cell, cradling the ingredients against his heaving chest with one arm and using the other to pull himself over the floor. Doorjamb, towel with shattered concrete underneath it, solid concrete. He dumped what he was carrying in the Circle, then continued on to Dean's chair. He grabbed his calves. They felt strange, inside the legs of his jeans. Dead. Sam pulled himself up onto his weak knees.

There was a noise, far away. A hoot, a whoop, he couldn't tell. His heart jumped in his chest, but he focused on Dean.

Assuming the vessel – Dean's body – had stopped working as soon as the last of Dean's essence had been dragged out of it by Gordon's exorcism, he'd been clinically dead for just over an hour now. Not that long. He'd cooled down, but not completely. Rigor mortis hadn't set in yet. His face, pale and slack, was aimed down at his lap, head dangling limply. His eyes were still clear, if empty and half-closed. Sam knew he couldn't afford to waste any time, but he took a second to look at him anyway, thinking that he really looked more like a porcelain doll version of himself than a dead body. He was almost beautiful like this. He looked much younger, much more relaxed.

Sam undid the straps first. Then the chain – he hurled it across the cell, resenting it for holding Dean in. The fishing line that held the handcuffs together had already been broken, probably during the exorcism, so he didn't worry about that. He pulled the duct tape off the collar and threw the two halves away. At that point, he'd hauled himself up onto Dean's lap, but now he slid back down onto the floor and pulled the body off the chair. He caught him with a grunt, at least a hundred and eighty pounds of dead weight.

He wasn't handling a corpse, he told himself as he laid Dean out on the cool floor. This body would be alive again within minutes. But he still closed the glassy green eyes, for whatever reason.

He dumped all the herbs together in a mixing bowl at Dean's head, a candle on either side of it. He pulled the lighter out of his pocket. After touching the flame of it to the wick of each candle, he held it to the top of the pile of herbs in the bowl. He flinched back, slightly, when they went up like a sparkler. The middle of the pile was reduced to soft, sticky ash, while the edges smoldered in a ring of heat. He reached into the bowl, dipping his fingers into the warm ash, then used it to draw on Dean's forehead. An inverted pentagram enclosed within a circle.

Sam let out a deep breath, closing his eyes briefly. He wiped his ashy fingers on his jeans, then dragged the heavy, leatherbound spellbook over to himself. He opened it on his lap, flipping through the cracking vellum pages in order to find the incantation that he needed. It was in Icelandic. He really had no idea why, but at least it was written phonetically, so he could read it.

It was long, spanning ten pages in a tiny, handwritten script. Sam's tongue and throat were aching with overuse by the second page, but he kept going. He had to get Dean back. He visualized the awkward, foreign words as fishhooks, dug into the demon's soul, dragging him back up out of Hell.

He started to see some results by the seventh page. Dean's fingers twitched. His feet inside his boots. His fingers, his arms. His eyelids. His hips. His hands clenched into fists on the eighth page. If Sam squinted, he could see thin strands of black floating around Dean, flowing up from the concrete floor and inching into his mouth, eyes, nose, and ears. He would've liked to keep an eye on those, but, unfortunately, he had to keep reading.

Dean's eyes opened on the ninth page, clear and focused, black as stormclouds. And bulging out of his sockets, the muscles around them taut and solid, like he was panicking. Which Sam realized he definitely was, as soon as he finished the last page. Dean's mouth popped open and he screamed like he was being skinned alive.

Sam winced away from him, unable to stop himself as the sound bored into his ears. He got a handle on himself then, though, and tossed the spellbook aside, reaching to move the candles and bowl as Dean sat upright so fast he swore he heard his spine creak. He'd stopped screaming. Terrified, panicked half-sobs were pouring out of him now. They punctuated him grabbing, violently, at his body, chest, arms, legs, shoulders, face, wrists, neck. Sam didn't think it'd be wise to interrupt him.

Dean curled up into a ball, hands cupping over his ears as he dug his fingernails into the skin on the back of his head. Sam was sure that he would have been pulling on his hair if it had just been long enough for him to get ahold of it. He scooted away from him, just a little, the movement instinctive, when the sobs petered out and he began to make a high-pitched, broken keening noise. It came out of his chest. Sam lifted a skinned hand, then let it drop. He wanted to touch Dean. But he wasn't sure what kind of effect it would have on him. Swallowing as Dean started to tremble and rock, he licked his thumb and forefinger, numbly pinching out the candles. There didn't seem to be anything else he could do right now. It reminded him too much, horribly, of when Dean's memories had come crashing back into him, the good with the bad all at once.

It was a few candles later that the terrible keening, which had started to grate on Sam's ears and heart alike, resolved itself into recognizable words. Sam's stomach clenched.

"S-Sam…Sa-am…Sam – "

"I'm – " His mouth, dry, failed him as he pinched out another candle. He swallowed again, trying to summon saliva, and managed to speak this time: "I'm right here, Dean."

He'd just barely put out the last candle, finished speaking, when Dean glanced over his shoulder with a lightning quick snap of his neck. Sam blinked, which was how he missed being yanked against Dean's chest and pretty much cocooned in his arms. And his legs; he wrapped his legs around him, too. Sam bit back a gasp of pain at the molten lava that the rough movement had poured over his leg, head, and face, but Dean didn't seem to notice his pain anyway.

He held him like Sam was a life preserver in a rough ocean, burying his face in the crook between his neck and shoulder as he slowly quieted. He felt for his long hair with one hand, tangling his fingers deep inside of it and stroking it repetitively with his thumb. As if reassuring himself that it wasn't going anywhere. Sam wasn't really sure what he should do, but, hesitantly, he put his arms around Dean, and started rubbing his back, between his shoulder blades. He heard a scratching and a crunching outside, and tensed slightly, but it was far away, and he'd give Dean as much time recover as he needed. He felt him breathing heavily, his heart pounding. It was a while before he spoke.

"How long was I gone?" he asked huskily.

"About ninety minutes," Sam replied. He hesitated, briefly, before asking a question of his own: "How long was it for you?"

"Week," Dean mumbled, and a chill shot down Sam's spine. A week in Hell. He couldn't even imagine. "I was in deep. None of the Lords found me or anything, but there were a ton of weaker demons – too many. Couldn't fight 'em all off forever. They were excited to have a Knight to play with. Fucking bastards."

Sam swallowed what felt like a bowling ball made of guilt before beginning, "Dean, I'm so sorry, I should've hurr – "

"Where's Gordon?" Dean interrupted, pulling back and putting maybe an inch of distance between them.

"Uh…dead," Sam replied. He was sure that the reality would hit him later, but right now, with so many other pressing matters to focus on, he was kind of detached.

"He do this?" Very, very gently, Dean touched Sam's swollen eye, then the tender knots on his forehead and jaw. After Sam nodded (instead of sarcastically remarking that he obviously hadn't done it to himself), Dean shook his head. "Jesus. You look like hell – and I should know." Sam snorted. "If you hadn't already taken care of him, I'd rip his lungs out…how'd you do it?"

"Broke his neck," Sam replied, not all that eager to talk about it.

"How? Your damn hands were tied to a chair."

"I…uh." Sam cleared his throat. "I used my feet."

Dean stared at him for a second, then shook his head again, snorting softly as he looked away. "Yeah, totally figures that you only whip out the awesome ninja Batman moves after I get exorcised. Just my luck."

"It wasn't as cool as you obviously think," Sam replied, shaking his own head.

"Yeah, whatever. Like I'm gonna believe you. Nerd." Dean glanced over his shoulder, out of the cell, then looked back to Sam. "So. We took care of Gordon. Not exactly the way that we wanted to – or you wanted to, at least – but still. We did it."

"Yeah, I…guess we did," Sam agreed. I did it.

"We should take care of you now." Dean touched Sam's eye again. Sam opened his mouth, but Dean continued before he could say anything. "But…ninety minutes. Gordon took up almost a whole hour. There were a few hours before that." Dean maintained steady eye contact with Sam as voices, faint, approached the cabin. The boards of the porch creaked. "Which means time's run out. We've got company."

Sam swallowed, taking fistfuls of Dean's T-shirt and squeezing them nervously. He was afraid again, for the first time in a couple of hours. It wasn't, he decided, something he liked feeling.

"Yeah," he agreed, huffing out a breath. "I guess we do."

"Okay, we've gotta leave." Grunting, Dean climbed to his feet, Sam's hands in his. He tried to help him up. Sam rose the few inches that Dean had lifted him, then fell back down, still sitting on the concrete floor. "Sam…"

"I…" He had not been past the first bend in the road that led to his cabin in five years. Every single thing he owned was in here. He had no money, food, clothing, or weapons without this place. But none of those things were why he hadn't stood up. He didn't want Dean to think it was because he was throwing a tantrum about leaving his house. Like a toddler or something.

"We can't defend this place," Dean was explaining. "Not against everyone that they're gonna have brought - "

"Dean, I can't walk," Sam interrupted. "My left leg won't hold me. Not after what I did to Gordon. A-and my right one's cramping pretty bad. From…crawling around on the floor."

"You can't walk," Dean repeated. Sam shook his head.

"Not right now." Uselessly, he added, "Maybe tomorrow."

"Okay." Dean nodded. "Not a problem."

"How – " Sam trailed off into a surprised yelp when Dean simply scooped him up, cradling him bridal-style in his arms. He put a hand on his shoulder, holding onto him, slowly relaxing as he realized that he wasn't going to drop him. "What're you…?"

"Carrying you. We're going right now," Dean replied, turning and walking out of the cell. Sam's legs swung limply.

"You can't carry me," Sam protested, glancing up at the ceiling as the roof creaked under somebody's weight. "I'm bigger than you are – "

"Yeah, in height, maybe – oh, shit." Dean swung rapidly away from the window over Sam's sink as a feminine hand, smeared with grime and dried blood, slammed against the glass. The line of salt on the windowsill prevented it from breaking through. "I'm stronger than you." He headed for the back door, turning, lowering his shoulder. "Tuck in, Sammy."

"No, D-Dean, wait, I need my – " He wasn't going to stop. Sam tucked his arms in and curled into Dean's chest, a small child hiding from something frightening.

"We don't have time, Sam!" Dean yelled it out as his shoulder struck Sam's back door and the heavy wood splintered like particle board. Sam closed his eyes, lowered his head.

"Hug the side of the house, there's a devil's trap," Sam warned rapidly into one of Dean's pectorals. Dean obeyed him. He left his stomach behind as they made an impossibly-sharp turn.

"Head down," Dean growled. People shouted and screamed in at least six different languages. Snarls, shrieks, hisses, chittering – a storm of sound surrounded them. "Just keep your head down." Sam felt Dean move, swerve, jump, dodge. Probably avoiding blows. He wondered how many demons there were, but the risk of losing half of his face was too great for him to risk a look. "And try to bring your legs – " What felt like a vulture's talons ripped across the bare skin of Sam's right foot, tearing out ribbons of blood and flesh. Sam screamed through gritted teeth, eyes wide and dry against Dean's chest. " – oh, fuck, dammit."

"Where – " Sam caught his breath, clutching at Dean's shirt. "Where are we going?"

"Outside your circle," Dean replied. "I've got a long way to teleport, and I can't do it with salt all around me."

"Where are we going after – "

Dean jumped to the side and rolled. Somehow without hurting Sam at all. Besides the pain in his torn-up foot, of course. And his concussed head. Back on his feet, he kept running. Sam was shocked into silence.

"Place I know," Dean said shortly. "Safe place. I can take care of you there." His fingers flicked through Sam's hair. "Your foot, your legs, your eye – your head – "

Dean stopped, dropped into a crouch, and skidded. Something above them howled in frustration.

"Almost there," he assured Sam, who turned his face in order to look up at him. He could see just enough out of his bruised eye to tell he was grinning down at him. "Feel like you're in Twilight?"

Sam glared, as best he could with a highly-damaged eye. "Eat me."

Dean chuckled, looking up and focusing on what was in front of them again. "Not until your concussion clears up, Sammy." He jumped again. Behind them, something gibbered in what sounded like ancient Egyptian, and fabric ripped loudly. Dean grunted, but hit the ground running. "Everything's gonna be okay."

He adjusted his grip on Sam, going more for comfort now than protection, and Sam lifted his head. He put an arm around Dean's shoulders, looking at the pine trees swaying in a slight breeze, and steadied himself as the sounds of the other demons (and the bounce of Dean's footsteps) began to fade.

And then they were gone.