(AU where after Jack got locked up, he became an antagonist.)
Jack Kline, the Nephillim, has burned off the last remaining of his soul to save Dean, Sam, Castiel, and Rowena from the archangel Michael - the one that had crossed to this world. He was possessing Rowena - and Jack successfully choked him out of her and burned him out, absorbing his grace and becoming powerful once more.
But in the end, this sacrifice ultimately ruined Jack. Forever.
Jack is also your boyfriend. You began to grow closer to him, so did he, and finally you two shared your first kiss. It was wonderful. You felt comfortable, safe, and loved.. you never wanted to leave his side. But... You started to fear him. Just a bit.
He could not feel anything any longer - the thing that made Jack.. Jack.. was completely gone. So, all you could see was the cold body of what Jack used to be. Now, he's just.. Jack. Not the Jack you knew, and loved with all your being. This changed him. And now... He's out for blood. He's going to kill Sam and Dean. He's going to kill everybody. Now.. he no longer can trust any human.
After running away and attempting to make angels with Dumah, he was found and put in the Ma'lak box. This box could hold an archangel. But, he's not an archangel. He's so much more powerful, and after like a couple of moments, he broke out and left. Even though he's burned off his soul - You knew a place that he'd most likely go to hide away. It felt right, so you went.. And there he was.
In the middle of a forest stood Jack. He slowly turned his head to you. He knew that you'd find him.. I suppose that because of his strong power, he could sense you. It made you fear him a tiny bit more. One wrong move and he could just snap you away...
You approached him. Back turned, he spoke.
"Sam and Dean.. They were right. I'm a monster. I can't change that. So I didn't." He sighed. "Ive hurt people. Ive killed people. Not just from before, but just now I wiped off an entire town with just the flock of my hand. The power is overwhelming. I don't exactly care... Though I don't wish I did, either. It's better to not care then care and feel the emotion."
His voice was devoid of any emotion, just a dark empty put that could nearly swallow you whole. What do you do....