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Dean sat at the foot of his bed, forearm stretched in front of him and fist clenched so far that his veins bulged from his muscles. The Mark of Cain bore back up at him, a daunting reminder of the choices that he had made and the path that he was now on. Controlling it was much more difficult than he ever thought, even with Cain’s warning. The pull to do terrible things and watch the blade rip through flesh and bone was almost too much to bear, along with the ever present whispers in his ears. The impulse would win soon enough and Dean feared he would have little to no say in it.
Suddenly, the door to his bedroom creaked open slowly, revealing a shadowed figure in a long trench coat. It was the blue eyes that grabbed Dean’s attention first, heartbreak and confusion shinning bright.
Dean lowered his head into his shoulders and growled like an animal, feeling the adrenaline beginning to course through his body. Visions of the angel’s blood splattered against the walls filled his mind, more vivid than any dream or vision had ever been before.
“Get the fuck out,” Dean snarled.
The angel in question blinked in surprise at the sudden harshness from the man in front of him. “Dean,” he started calmly.
Dean grabbed the nearest object that he could find, which just so happened to be a glass cup on his nightstand, and hurtled it in the angel’s direction. It shattered right at the angel’s feet, though he hardly reacted other than a slight flinch.
“This is your last warning, Cas. Get out!”
Castiel gave his head a small shake and took a step forward, flicking his wrist so that the door closed behind him. He began to prowl around the bed, giving enough space that Dean couldn’t easily reach out to strike at him if he felt the desire to. The person in front of him wasn’t the man that Castiel remembered, and he had to keep that in the back of his mind as he tried to communicate with him.
“You know that I can’t do that, Dean. Not when you’re like this.” Castiel took a step to the side, feeling his angel blade move with him from where it was tucked up into his sleeve. He didn’t anticipate needing it, but it gave him a sense of security to know that it was there.
“And you think you know everything, do you,” Dean seethed, saliva flying from his bottom lip. He clutched the First Blade tightly in his hand, fingers stretching all the way around the hilt until his joints howled in protest.
“You know that I do not,” Castiel continued evenly. “But, I do know that whatever you’re going through, you don’t have to go through it alone. The Mark of Cain is hell to bare, that part is true. You holing yourself up here and closing yourself off from Sam is not the way to deal with it.”
Dean scoffed in distain. “And I suppose you’re here to talk some sense into me?”
“I’m your friend, Dean. This is what friends do. I want to help,” Castiel explained.
“And what would you know about being a good friend?! You’ve caused me nothing but pain since you reared your feathered head. You think I want to have you around after everything that you’ve done? You screw up everything you touch!”
Castiel fought not to show that Dean’s words had sliced deep. The eldest Winchester knew exactly where to push and what to say to get under his skin, and Castiel had to remind himself that reacting in a way that Dean wanted was a surefire way to make it worse.
“That is not the Dean that I know,” Castiel murmured after a moment, more to himself than to Dean.
Dean’s eyes glowed in malice as he rose to his feet, still pressed against the bed. “Is that so? You think you know everything about me, Castiel,” he taunted, Castiel’s name spat out of his mouth like poison. “What am I thinking right now?”
Although contrary to whatever Dean believed, Castiel couldn’t read his mind and he wouldn’t dare to if he could. Those thoughts were too dangerous right now, too daunting for even an angel to tackle. All he could hope to do was keep the situation from escalating if at all possible.
“I know more than you believe that I know, but no, I do not know everything,” Castiel responded after careful consideration to each word that left his mouth.
Dean snorted in amusement, head thrown back and forth almost aimlessly. “Yeah, that’s what you think.” He raised a hand and ran the First Blade over his open palm. It wasn’t quite enough to draw blood, but it still look like it stung all the same. A shiver ran down Castiel’s spine as he wondered what it must feel like to Dean to hold all that ancient and dark power and be almost a slave to it. He had seen what it had done to Cain back in the day and now he was witnessing it all again.
“Liar!” Dean spun around, a fiery glow burning in his usually calm gaze. “You’re a fucking liar!”
Castiel gave a feeble shake of his head. “No, I’m not.”
Without missing a beat, Dean surged forward and slammed Castiel against the wall with the First Blade pressed against his neck. Castiel could feel the slight pressure and prick at his skin, knowing that if he so much as allowed his vessel to take a deep breath it would slice through his skin and spill into his flesh.
“Do you want to say that again,” Dean questioned, breath hot on Castiel’s cheek.
Ordinarily a situation like this may make Castiel feel something else for Dean besides horror. His heartbeat skipped sporadically in his chest as he scented aftershave and mint toothpaste from Dean’s skin. He wanted nothing more than he push Dean off of him, and share a conversation with the man that he knew and cared about. Unfortunately, it seemed that these days were over.
“You’re sick, Dean,” Castiel grunted, slightly squirming. “Sick with a curse brought on by the Mark of Cain.”
“I’m better than I’ve ever been, Cas. You’re just too blind to see it.” His teeth momentarily ground together before he pressed even harder against Castiel so that their bodies were flush against one another. Castiel could feel ever tense of Dean’s muscles, his heartbeat and strong breath against him. The First Blade was still raised to Castiel’s neck and he couldn’t move even an inch.
Castiel looked to Dean and suddenly saw his eyes flood black, teeth suddenly bared. Castiel fought a telltale yelp, knowing how Dean would take that and use it against him.
Dean he could deal with; Dean like this was a completely different story.
“I can smell your fear.” Dean pressed the jawbone against Castiel’s throat and swiped aside, watching it slice through and leave a trail of dripping red in its wake.
Castiel let out a deep breath through his nose before reaching up his hand and placing it on top of Dean’s forehead. Power pulsed through his body as he fought the impulse to smite Dean and force the darkness from him. He wasn’t even sure if it was possible with whatever Dean was now and he was certain it wouldn’t go as plan, but the desire was certainly there.
Dean let out a harsh cackle that had Castiel almost stumbling back. The voice wasn’t Dean’s, nor was the soul.
“Do it,” the voice hissed, strangely high pitched and shrieking.
Castiel gave his head a shake before drawing back, allowing a shiver to take over his body.
“If this is what you want, I’ll leave you to it. But know I’ve seen where this ends and it won’t end the way you think it will!”
Dean twirled the First Blade around in his hand, watching Castiel out of the corner of his eye. He wandered back to his bed and sat down heavily, fingers flexing and gaze hungry. He set the First Blade strategically in front of him, though his eyes never left the angel in question.
Castiel ducked his head into his shoulders. “You’ve made your choice, I see.”
Dean still said nothing, though the black hue was back in his eyes. He backed out of the room slowly, careful not to let his gaze wander from the experienced hunter. Dean may have been taunting him before, but if the sting at his neck told him anything, it was that Dean was dangerous.
Castiel slammed the door closed and backed down the hallway, fingers tracing the nick in his throat. He allowed his grace to heal it, though part of him wished he would’ve left it or at least let it scar. It would be a harsh reminder of what was happening to the man that he cared the most about.