The urge was overwhelming. Every day the itch to take the blade in hand and bathe it in blood grew stronger. Holding the blade terrified me beyond anything, but it also gave me a high I secretly never wanted to let go. I wanted to watch the lives of the innocent and the unclean slowly wash out of the eyes of my victims. I wanted to squish their red essences through my finger tips and smell the coppery bliss. Most of all, I wanted to watch the red splatter of blood burst from my brother like shattering glass. The feeling of Sam's blood covering me and my blade was the one thing I dreamt about day and night. I know, it's sick and I hate myself for having such longing for those dreams at night. Yes, dreams. Not nightmares. I've tried to tell Sammy something was wrong, but it's like I'm split in two. The old me wants to warn Sam; to save him. The new me, Mark of Cain me, wants to kill him in the most agonizing of ways. Sammy's noticed something different about me though. He's asked me about it, but all I say is that I'm fine. He, of course, calls me a fat liar, but he doesn't push. I wish he would. I wish he'd shout and scream at me so I could finally force the words from my lips. I've held myself back from harming my sweet little brother, but I can't any longer. The call for blood and death is too strong now. Stopping myself from doing the deed again would only kill me. I'm no longer Dean Winchester. I am now simply the mark's puppet. It has fully possessed me over the days I've bared it and now it wields me like a sword. That's why I now hold the boned blade in my hand. The mark glows red hot against my skin, but all I can feel is the power and hear every soul on the planet calling for me to rip them apart. A small, disgusting smile curls around my lips as I imagine bathing in the blood of all God's children. It's sick and yet, refreshing. Slowly, I take my time as I make my way to the living room. Not once do I look up at the mirrors on the wall. If I did I wouldn't see me. I would see a man with slightly darker eyes that held no light. I hesitated before making myself present. I can sense another soul in the living room with Sam. This soul isn't technically a soul however. It's far grander than that, but it also doesn't fit with its owner. I smirk. Castiel. The old me, Dean Winchester screams in my head, thrashing his fists against the walls of my mind in attempt to break through.

"No! Don't! You can't!" Dean Winchester shouts, but I ignore such words. Sam's blood was one thing, but the blood of an angel? Oh, now that was something I couldn't pass up on. "Don't you touch them, you sick son of a bitch!" Pushing the curses of the righteous Dean Winchester to the side, I walk into the living room. Cas and Sam are chatting with one another. I hear Cas mentioning a gang of angels, but I'm not paying attention. All I can hear is the flow of his grace and Sammy's soul. They beckon to me, pleading to rip them to shreds. Cas hears me enter and looks up from Sam. At first there is a pleasant smile on his face that is full of friendship and loyalty, but soon it dissipates. His eyes fall to the mark on my arm and the blade in my hand.

"Dean, what have you done?" the angel gasps at the sight and Sammy chose that time to turn to face me too. Dean's brother's eyes widen at the sight of me and I lick my lips as I feel the fear radiating from the two.

"Dean's not here right now, Angel," I hiss, lifting the blade up and pressing its cool edge to my lips. "There's only me left." The mark on my arm grew hotter and brighter and Castiel's eyes widened.

"Dean…" Sam trailed off as I lunged. I close my eyes, feeling the high return as I feel the blade bush through soft skin, muscle, bone, and then an internal organ or artery. I couldn't tell with my eyes closed. Hot blood poured over my hands and I open my eyes to meat piercing blue ones. I freeze, two reactions hitting me at once. The damn angel had stepped in front of the younger Winchester protectively and now my blade had torn through his skin right under where his ribs connected. Pain flashed through those blue eyes and blood bubbled from his lips.

"Cas..." Dean's voice escapes from my lips as I lose concentration over my hold on the damn Winchester boy. Castiel's dimming blue eyes light up at the sound of the familiar nickname and I feel his shaking hands on my shoulder, squeezing gently.

"Dean," the angel gurgles and I feel Dean fight my hold on him that very moment. A gnash my teeth together in anger and push the blade in farther. Cas bites down on his pink lips, forcing down a cry. "Dean," Castiel tries again, trying to get through to his friend currently locked in the vaults of his own mind. I hear Dean calling back inside my head and I've had enough. I twist the blade hard; tearing whatever is left in Castiel to pieces. A cry finally bursts from Cas' lips and I pull my blade free. The angel crumples to the floor in a bloody heap and I lift a blood covered hand to my face and take in the coppery sent. I hear Dean shouting and maybe crying a little too. One down. I raise my eyes to Sammy, who is staring at me in disbelief. "Sammy! No!" I run my bloodied hand through my hair, momentarily tainting the blond strands with Dean's best friend's blood. I start to come closer to the younger Winchester, but not once does he step back or flinch from me. He only stares with wide eyes. I lift my blade so the point is resting against his throat and push gently.

"Drop the blade, Dean," Sam orders sternly, trying to hide his fear from me. I tilt my head forward so we're nose to nose. His blood smells so good.

"Not this time, Sammy," I whisper huskily.

"We know you're in there, Dean." I roll my eyes as I chance a glance to my right. Castiel is back on his feet, pale, gushing blood, but still very much alive. Honestly, does that fucking bastard ever die when he should? "This isn't you. This is the blade. Let it go Dean," Cas forces from his bloodied lips. I smirk at his effort. It's useless…

"Sammy, Cas..." I cover my mouth before another sound could leave my mouth. How did he gain control like that? Something pounds against my head as Dean begins to fight back. Too bad for him I'm stronger. I drop my blade to where Sam's heart beats and begin to press against the fabric of his plaid shirt. Sam grimaces, but does not give me the shrieks I've dreamed about. I frown, disappointed. Before I get the chance to push my blade deeper Castiel pushes me to the floor and holds me down. I struggle against him, kicking my foot against his wound and sending him flying into the wall. His body crunches against the wall and I go to lunge at him, but Sam grabs me. I gasp as Sam pulls me into a tight embrace. I try to pull away, but Sam only clings tighter.

"Dean, you can fight this," he whispers. "You've fought for me so many times. You fought monsters for me, demons, and angels. You even saved me from death. Hell, you've fought for Cas just as much. You hold so much guilt on your shoulders already, Dean. Don't add anymore. Just fight for me…for us one more time." There is a heavy silence. I struggle, mind burning, but I'm still in control. I lift my blade to stab it into Sam's back, but another set of arms embrace me and this time it's Castiel. He's soaked in blood and looks like he may pass out any moment from his wounds. I feel Cas' hand snake up mine until his hand is squeezing the hand I'm holding the blade with, keeping me from slashing it down into Sam's spine. "Dean." My attention turns from Cas to Sam again. There are tears in Sam's eyes as he smiles at me. "I need my brother."

"I need my brother as well," Castiel joins in. I snarl, tightening my grip on the blade, but I stop. Excruciatingly hot pain burns through my mind and I scream in agony. The mark on my arm sizzled and sputtered as I lost control over Dean's body. Cas and Sam stay latched on to me until everything erupts into red fiery light.

When I open my eyes all thoughts of blood and watching the life drain from my brother and angel are gone. My thoughts are my own and The Mark of Cain is gone from my head. It's like someone flipped a switch, giving me control at last. I chance a glance at my arm to see that the mark had burned away and raw flesh was all that was left in its place. The blade slips from my fingers and as soon as it clatters to the floor Sam pulls away from me and Cas slumps to the floor, but the angel still holds my hand. Terror thrums through me as I remember what I…what the mark had made me do. I push back the layers of clothing covering the wound, preparing myself for the worst, but all I see is unmarked skin. I blink my eyes a few times. It's like nothing happened.

"Gabriel wasn't the only one that could fake a stabbing," Cas said with a small smirk on his lips. I slap the angel's arm before pulling him into a tight hug.

"Don't ever do that again, you stupid son of a bitch," I whispered softly before pulling away and turning my gaze to Sammy.

"Thank you," I said and then turned so I was looking at both my brother and angel. "…both of you."

"Well, we couldn't let you go dark side on us when we still have the Hell campaign and Fallen Angel fiasco to take care of yet," Sam stated, before leading the way to the library. I follow him and Cas, closing my eyes as I walked, relishing in the feeling of being myself again. All cold thoughts had left me. I can think for myself and no longer fear on what I'd do to my brother and best friend out of a lust gained from some stupid mark. I wish I had asked about the effects of it right away. Maybe none of this would have happened then. Yes, now we are down the one weapon that could have given us any chance against Abadan. But I'd spend the rest of my damn life fighting the bitch if that meant I'd keep my free will and my two brothers.

Well, after watching S9E16 this just popped into my head. It's not perfect, but I like it. Thanks for reading!