Dean is off to work and Cas is home alone. He had to take Cas' car because he couldn't find neither his keys nor the spare key for his baby. He seemed a bit pissed that he misplaced both keys. In reality, Cas hid them for the sake of trying to find evidence of his fears.
Cas looks through the house, trying to find anything that could point towards Dean being Cain. Cas doesn't want to believe it. It's all he wants for it to be the wrong. For all of this just to be some crazy notion he made up. He knew his obsession with the killer wouldn't be good for him in the end, but he couldn't help getting caught up in it all.
The last room he looks through is their bedroom. Nothing in the closet except some old keepsakes from Dean's parents. The dresser is filled with clothes and- Cas' face reddens at the sight of the purple dildo Cas finds in Dean's sock drawer. He had no idea Dean owned it. Cas shoves it back into the drawer before his thoughts can wander about that. He needs to stay focused on the topic at hand.
Cas finds something when she searches beneath the bed. It's a book. At first it appears to be a normal, leather bound book, but Cas notices a faint indentation of the Mark of Cain. Cas opens the book. Each page shows a picture and obituaries of every victim of Cain. And every single one has a date written in the bottom corner, no doubt these are the actual dates each victim was killed and not the estimated date the forensics found.
Cas buries his face in his hands. He's so scared. What would he do if Dean really is Cain? He has no clue. All he knows is that he is terrified.
With a heavy heart, he sets the book on the bed and goes out to the car. The car is as immaculate as ever. Even the trunk looks clean and practically empty. Cas doesn't a thorough sweep, making sure he doesn't miss anything, and he nearly does. Just as he's about to close the trunk he spots and odd seam on the floor of the trunk. He runs his hand along it, realizing that it is a hidden compartment.
"I can stop now," Cas says quietly to himself. "I don't have to know." but with a deep breath he opens it. He gasps at the sight of the blade inside. Along with the blade is a pair of black leather gloves. This is the evidence he was looking for. There is no doubt in his mind now. Dean Winchester is Cain.
Dean pulls into the driveway at nearly six in the evening. He's in a relatively good mood. For no reason in particular, he's just in a good mood.
"Cas, honey, I'm home!" Dean calls as he walks through the front door. He's met with silence. "Cas?" still nothing. Maybe he went out for a walk. Dean thinks to himself, but that can't be, Cas would never leave the front door unlocked if he left. "Cas!" Dean calls a bit louder. He checks the living room and kitchen with no sign of his boyfriend.
Dean enters the bedroom and freezes. Resting on the bed is the last thing he'd imagine there. His blade is sitting in the center, one glove on each side of it, and his book above it. Dean steps up to the bed, staring at his objects.
"It's you isn't it?" Cas' voice sounds behind him. Dean sighs and turns to face Cas.
"Where were you, I called out." Dean asks casually.
"Dean, is it you? Are-" Cas takes a deep breath. "Are you Cain?"
"Cas, hang on-"
"Just answer the damn question, Dean." Cas snaps.
Dean huffs a laughs and shakes his head, though he finds absolutely no humor in the situation whatsoever.
"Yes," Dean sighs. "I'm Cain." Cas' heart plummets when Dean says this. He knew it was true, but actually hearing it just makes it so real.
"I can't believe it," Cas stares wide eyed at Dean.
"What gave it away?" Dean asks.
"I would wake up to find you missing during the nights, only to find out later someone was killed that night. Then little things started adding up." Cas holds his head high. "Sam would never suspect you because you're his brother. The thought has never even crossed his mind. So you have the perfect cover."
"Cas, just listen," Dean takes a step toward Cas.
"Don't!" Cas steps back. Dean hates to see the fear in his eyes.
"Cas, it's still me. I'm the same guy you fell in love with." Dean says softly.
"I didn't know you were a killer then." Cas replies.
"The people I killed deserved to die." Dean says defensively.
"Even Jessica?" Cas demands. Dean let's his shoulders sink.
"If there was one thing I could take back, it would be her death. She was gonna tell Sam and I-"
"I don't want to hear it." Cas cuts him off.
"Cas, you know I would never hurt you. I wouldn't be able to live with myself if I ever did." Dean goes to move forward, but thinks better of it. He doesn't want to see the terror in Cas' eyes again.
"Have you ever thought about it?" Cas stares at him. Dean remains silent, not being able to deny it. He had thought about it, more times than he would care to admit. But he knows beyond anything that he would never be able to actually hurt Cas.
"I can't believe it." Cas gasps.
"Cas, I would never be able to. I saved you, I couldn't hurt you." Dean can see the panicky look on Cas' face and can tell he's ready to bolt.
"I have to go," Cas takes another step back.
"Wait, please don't." Dean moves forward a bit too suddenly, Cas jumps back.
"Goodbye, Dean." Cas turns and takes off. When Dean hears the car speed off he turns and slams his fist into his wall, leaving a huge hole. He never should have been so careless. His anger is flowing through him. In a rage he shoves everything off his dresser and rips the blanket off his bed, causing his book, knife, and gloves to go flying.
He stares at his mess, huffing out a breath. Despite Cas leaving, Dean knows there is no way he would tell anyone. He's probably suspected for a while now and he didn't say anything then. He won't say anything now, or so Dean hopes.
Casey on the other hand is forcing himself not to cry. He doesn't know where he's going, but he just needs to get away. Fear grips at him when he thinks that he could have been just a face on a page of Dean's book.
I would never hurt you
I saved you
Dean's words float through his mind. Then suddenly he's his with a memory of a conversation they had a while ago.
"... what if Cain comes after me?"
"no, Cain would never come after you. He saved your life, he wouldn't kill someone he feels he protected from harm. If anything, he would kill anyone trying to harm you."
Cas keeps thinking about this as he drives. After making a quick call, he heads towards the home of his best friend. He just needs to think about all this. He needs to think about what this means for him and Dean.

YOU ARE READING
Murder Mayhem
FanfictionDean Winchester spends his hours as the local mechanic, but in his free time he slices and kills. His own brother is working the case to find this killer. Cain is what they call him and Dean relishes in it. His next victim is accountant Castiel Nova...