Dean's POV

It has been 6 months since Greyson was born, and things were going great until the last month. Greyson aged faster than human kids, even though he was only 6 months old he looked and acted like he was a year old. 3 weeks ago Cas and I were enjoying down time in the bunker with our son when Sam came into our bedroom talking about possible Demon activity, which had us all on edge since we hadn't had much Demon activity since Sam stopped the trials to close the gates of hell. Of course we knew it would happen again at some point but this seemed to be on a larger scale than normal, something was wrong. We figured out it was Abaddon was making a move towards taking over hell in Crowley's absence since the trials. We were following a trail of bodies, both former demons and humans across the country and Sam and I were getting close until we found Crowley a week ago. Sam headed back to the bunker to check on Cas and Greyson while I decided to talk to Crowley.

"What do you mean there is only one thing that can kill Abaddon?" I asked in an annoyed tone.

Crowley rolled his eyes and replied in his smug Scottish accent, "Pay attention Squirrel, your almost as bad as Moose. Abaddon is a Knight of Hell, she can only be killed with The First Blade."

My eyebrows went up to my hair line and I asked, "So where can I find this thing?"

Crowley looked a little hesitant for moment but then replied, "I just happen to know where to find it." Before I could say anything Crowley snapped his fingers and we were outside an old farmhouse.

I looked around confused, "This supreme, mother of all weapons is here? In a run-down farm house? Really Crowley?"

Crowley rolled his eyes again, "Well considering the weapon belongs to Cain and this is where Cain retired yeah,"

"Wait Cain as in, like Cain and Able?" I asked incredulously.

Crowley smirked and nodded, "Wow Squirrel actually knows his bible lore."

I groaned and stopped myself from punching Crowley in the face, "So what are we stealing it or what?"

Crowley seemed appalled at the idea, "No you nutter we are going to ask him to borrow it."

At first I thought he was being sarcastic until he started up the stairs, was about to knock and then turned to look at me waiting for me to come up the stairs. I was shocked but followed him up the stairs and just when Crowley was about to touch the door it opened, and there stood a dirty looking man with long hair and a full-grown beard. He looked at me and then Crowley and shook his head, "You aren't welcome here."

Before he shut the door I blurted out, "We need the First Blade."

Cain turned around and eyed me, "And why do you think you need the First Blade?"

I took a deep breath, suddenly feeling a little bit nervous. "I need to protect my family, I am going to kill Abaddon."

Cain laughed, "What make you think you are capable of killing Abaddon."

"I'm a hunter, I kill things like her for a living. My brother and I have stopped the world from ending a few times now." I said, I could feel myself getting pissed off at this guy.

Cain shook his head but let us in, he lead us to his living room and let us sit down before saying, "Do you want any tea?"

"No," I said calmly.

Crowley nodded, "Please, two sugars, and a splash of milk and a bit of honey if you have it."

I rolled my eyes at Crowley and Cain went into the kitchen to make the tea. After a few minutes he sat Crowley's cup in front of him and sat in a chair across from us. "Abaddon is not your normal demon, she is a Knight of Hell."

I nodded, "Yeah we knew that. We had sorta dismembered her, we were going to cure her in order to close the gates to hell but she got away. The last month she has been leaving bodies, human and demons. She is getting closer to where my family is and I am not letting her hurt them."

Cain listened to me and then stood up, "In order to wield the Blade there is one thing you need."

I stood up as did Crowley, "So does that mean you'll give it to me."

Cain nodded, "On one condition, after you kill Abaddon, you come back and you kill me."

I couldn't stop myself from asking, "Why?"

Cain sighed and looked at a picture on the mantle, "I am tired of living, after the Knights of Hell kidnapped and killed my wife I killed them, all but Abaddon. And as a promise to Collete I stopped killing so I never hunted her down, It is my fault she is killing again, now Dean you need this in order to use the Blade."

Cain rolled up his sleeve and there was a mark, that looked almost like a backwards F burned into his arm. Crowley stepped back and did a little cross on his chest. I looked at Crowely and rolled my eyes, "Really?"

He raised his voice, "It's the bloody Mark of Cain!"

I sighed then looked at Cain, "How am I supposed to get that?"

Cain looked at Crowley then at me, "The Mark of Cain can be transferred to something the Mark feels is worthy Dean."

I nodded, "Okay, how?"

Cain to my left wrist in his hand and said a few odd words I couldn't understand and soon I felt an indescribable burning sensation go up my arm and watched as the Mark appeared on my arm. As soon as he started it was over and he let go. He then went to a room and brought back something wrapped in an old cloth, and for some reason I felt a pull to hold it. When he opened the cloth there laid the First Blade, made of a jawbone of a donkey, and I felt a pull to be holding it, Cain seemed to smirk a little nodded, "Go on Dean. It's calling to you isn't it?"

I gently wrapped my fingers around the weapon and felt an almost overwhelming power rush through me. I ignored the wrong feeling in my stomach and looked at it before putting it back in the cloth and wrapping it, even covered in the cloth I could feel the power pulsing to me. "Thank you. Once I've killed Abaddon I'll do as you asked."

Cain nodded and before anything else could be said the front door was slammed in and demons rushed in, I could tell they weren't Crowley's because they tried to attack, I pulled the blade out and started killing Demons left an right, Cain also helped and once we had barricaded the doors again he growled at me, "Get the hell out!"

Crowley grasped my shoulder and teleported us back to my car. "So,"

I rubbed a hand over my face and sighed, "Now I hunt down Abaddon and kill her."

Crowley nodded, "What are going to tell your angel?"

I growled a little, "It doesn't matter. You can go now."

Crowley scoffed and then disappeared. I looked at the Mark of Cain on my arm, gently running my fingers over it. I closed my eyes and sat back in the seat, just relaxing for a minute. Then I turned the car on and drove back to the motel I was staying it. I didn't know what I was going to tell Cas or Sam so I just wasn't ready to go and face them. I climbed out of Baby and went into the room, I turned on the TV to some random channel. It didn't take long for me to fall asleep but when I woke up 4 hours later I felt someone by me and I reached for the knife under my pillow and moved to attack but I stopped short when I saw Cas standing there. I sighed a little, "Damn it Cas you know better than to do that to me."

Cas was staring at the Mark and I could see tears in his eyes, "Do you have any idea what you just did to yourself Dean?"

I looked down, "Abaddon can only be killed with the First Blade, and I needed the Mark to use the blade…"

Cas shook his head, "And what do you supposed you are going to do after Abaddon is dead Dean?"

"I made a promise to Cain that I would kill him." I said with very little emotion.

Cas scoffed, "What about our son? What happens when that Mark twists you into something I can't even recognize?" I started to shake my head and tried to argue with him but he yelled, "Lucifer was the one originally with the Mark Dean! He changed and was cast out, he then gave it to Cain! And Cain murdered for hundreds of years Dean!"

I ran a hand through my hair shaking and let out a deep breath, "I needed to keep you and Greyson safe. Abaddon is closing in on the bunker…"

Cas kneeled in front of me and lightly kissed me, "We will figure things out…"

I kissed him back and pulled him close to me, "I just needed to protect you and Greyson…"

Cas kissed my head lightly and smiled, "Come home. Greyson has been looking for you since Sam came home."

I nodded, "Okay… Go ahead I will meet you at home."

Cas nodded then disappeared.