*A lot of dialogue in this chapter, sorry, but there's more to come. I really appreciated the support from the last chapter, thanks, and to whoever put the link to this on Tumblr, fucking thank you! I just happened upon it while browsing the mark of Cain tag and it made my whole day! Anyway, read and review.

The laughter from before was echoing across every wall in the bunker, traveling down every corridor. It was that that woke Sam.

He'd gone to bed, knowing from experience that he couldn't help Dean if he himself was exhausted, and he assumed Dean would be safely out cold for another few hours- wrong.

His eyes snapped open and he was instantly awake and alert. He slid out of bed, started cautiously down the hallway, he called out,

"Dean?!"

Only manic laughter responded. A sharp kind of horror clutched at Sam's heart the further he went as he realized his brother's already questionable sanity was unraveling at an alarming rate and there was nothing that could be done about it.

"DEAN?!"

The laughter was definitely coming from the armory and Sam began a silent prayer in his head that his brother hadn't done anything he couldn't deal with.

He sucked in a breath and pushed open the door slowly so as not to startle his potentially armed and dangerous brother.

Every canvas covering over every box was ripped down the center by what was undoubtably a serated knife. Writing was carved into the walls and Sam hesitated for a moment, taking the time to read some of the scratches:

Kill Kill Kill Kill

Cain killed Abel, Abel was saved, Cain was damned

Murder Mur

It trailed off here, a long carved line leading the cut off word to a new text that read:

I CAN'T STOP MYSELF

Sam felt tears sting at his eyes but they were blinked back when he jumped when he saw a movement to his left from behind a shelf. Dean wandered out, holding out his arm to show Sam. It was bleeding heavily from cuts surrounding the mark, all the same cut as the ripped canvasses.

"Sammy?" Dean asked, sounding lost but also sick, his voice slurring.

"Dean, what did you do?" Sam demanded, approaching slowly.

"I tried t-to cut if off. Di'nt work though."

Sam reached for Dean's arm to examine the damage and dropped it at the light touch.

"Dean, you're way too hot."

"Aw. Thanks, Sam. I always knew some day you'd accept- hey, hey, ow!"

Sam had grabbed Dean by the arm and was dragging him out of the armory. His older, slightly smaller brother struggled against him to no avail.

Out in the main room, Sam pushed Dean into a chair and knelt down in front of him. He grabbed Dean's forearm and extended it, ignoring Dean's wincing as he did so. He crossed to the room to the kitchen where he grabbed their first aid kit and then returned to Dean who he was a little surprised to see had stayed put.

He took Dean's arm and examined the surprisingly deep gashes that circled the mark but didn't touch it. Sam set down the bottle of whiskey in front of Dean and started threading his needle. He started stitching Dean's arm, slowly, carefully, afraid of what his brother might do next.

"Aw, piss off." Dean said, glaring over Sam's shoulder.

Sam looked back and saw nothing. He'd dealt with Lucifer long enough to know what was going on, he recognized the darting eyes, the stoney quality of them.

"What're you seeing, Dean?"

Dean ignored him. Continued to address the apparent character standing by the door.

"There's nothing wrong with me, alright? It's a fucking brand, every Frat boy in the South has one, it isn't doing anything to me."

Sam pulled at Dean's wounded arm, trying to get his attention back.

"Dean."

Dean turned back and looked at Sam, then almost immediately shut his eyes, tight. He looked like he was about to have an aneurism. He bowed his head, scraping his fingers against his scalp as he combed through his sweat-soaked hair.

"Not him. No, no, no. I'll carve apart any son of a bitch, gut them, strangle them with their own intestines... But not him..."

"Hey! Hey, Dean-"

Dean pushed Sam away weakly, stumbled to his feet, trying to get away, he fell to his knees.

"Dean!"

"I can't kill him, I can't. I won't..."

It looked like he was having a nightmare, but he was still semi-conscious.

"Dean, talk to me!"

His eyes fluttered open, unfocused and confused.

"Sam?"

"Oh, thank god."

Sam hauled Dean to his feet and returned him to his seat at the table. He pushed back Dean's hair on his forehead, feeling the extreme heat and he pulled the baby thermometer out of his pocket.

Despite the apparent fit he'd just had, Dean seemed to be recovering his demeanor quickly enough. Though still exhausted.

"Stick that in me again and I'll shove it up your ass, Sam." Dean argued but it was tired, halfhearted, struggling to remain present.

Sam ignored him and held the thermometer in his ear until it beeped.

"Shit, it's went up, it's 104 again, Dean, we gotta go to a hospital before your brain fries."

"Please, like they'd know what to do." Dean said, gripping the back of the chair in an effort to stand up.

"Hey, hey-" Sam stood up, taking Dean's shoulders, "Where are you going?"

"Ice bath, man, I gotta get my head on straight so we can find us a hunt."

"Woah, woah," Sam said pulling him back by his arm, "First, sorry but I'm at least gonna be nearby the bathroom, you'll pass out and drown in the tub."

Dean rolled his eyes, turning away, unconsciously clutching the burning mark.

"Second, what the hell would we be looking for a case for?!"

Dean turned on Sam, though his menacing mask was a thin veil and it was not overly convincing considering the heavy flush in his face and there was still a film of sweat over his face.

"For God's sake, man, if I don't kill something soon I'm gonna hurt somebody!"

Sam nodded, sighing in that very typical irritated Sam way.

"Okay. I hear you. But what if... What if you start hunting, killing things, and then you start killing people just-"

"I know what I'm doing, Sam, I know what's going on-"

"No, Dean, you don't. You're sick and you're violent and I can't let you go off feeding this-this thing."

"Sam, if I don't kill something, I'm afraid I'm not gonna be able to control myself."

"Control yourself from what?" Sam asked quietly.

"From hurting you." Dean said.

There was a long pause and Dean continued,

"I'm rabid, Sam. This is my last swing at this thing but if I can't get a handle on it..." He broke off, and Sam waited with a grave looking apprehension, "I'm gonna have to clean up my mess and kill the monster... I mean, that's what we do, right? Kill monsters?"

He extended the half-stitched wound that was encompassing the glowing mark.

"I'm a monster, Sam."