He wonders if this is what possession must feel like. Being trapped, chained down by the weight of his own body. Led around by something, in his head, that's just not him. Forced to be something he doesn't wanna be.

He went into that fight fully expecting to die. He wanted to take out Metadouche, and he might have succeeded, if that earthquake meant anything. But hey, you win some, you lose some. You kill some, you die, killing others. Or, attempting to kill others.

He never planned on coming back.

And, in a way, he didn't.

It did.

The ghost with the black eyes, and the jawbone of death. The creature with its predatory gaze set on his brother and his best friend. The dog, ordered around by the same Scottish asshole that gave it its leash in the first place.

The worst thing about this new life is that he's fully aware of how his fist is slamming into his brother's jaw. How Sam is flying through the air, from the force of his blow. It's be a miracle if something in him doesn't break.

He can hear the faint begging from his brother, as he clutches his bleeding nose.

"Dean. Dean, stop. You can stop. De-" He can feel his fist cut off his brother's panic. Sees his brother crumple to the floor, ready to be his newest victim.

He can't stop it, though. He needs this. Needs the kill. It's some primal, animalistic instinct, that forces him to lift the Blade.

"Dean, stop!" Cas yells, from behind him.

He feels his body tense. He hadn't heard Cas walk in.

Cas can't be here. It's bad enough, what he's about to do to Sam. He can't kill both of them. He can barely even life without one of them, without earning himself the Mark of goddamn Cain. There's no way he could survive without both.

For a split second, he regains control of himself. He's Dean Winchester again, in Dean Winchester's body. Not some Demonic thing. Not some alien creature. Just a lowly little human hunter.

He loosens his grip on the Blade, and lets it drop the the ground. He follows, soon after, overcome by the force lodged into his arm.

There's a loud chanting in his head, telling him to main, to kill, to destroy. Telling him how good it'll feel. How fun it'll be. How it won't hurt anymore, once he gets the kill. Not for a while, anyway.

There's no let up. The second he lets go of it, the Mark start telling him to grab it.

He can see Cas kick away the Blade. Can feel himself growl, in response, like the goddamn dog he's supposed to be. An inhuman, obedient mutt. The guy that you tell "Kill", and he asks you "How gory?"

"Calm down, Dean. We can fix this." Cas promises.

And how's that possible, when everything good in him is already broken?

"Get Sam out, Cas." He says, through clenched teeth. The Mark is burning now, as it tries to take back control. It sends liquid fire pouring through his veins.

"Dean-"

"Go!" He yells. A thick layer of black smoke forms on his eyes. He can feel it. It's the most uncomfortable thing he's ever felt.

"No." Cas says. He lays an arm on his shoulder, probably to comfort him. He lashes out, tearing himself away from the comforting hand. Cas takes a step back, slightly shocked at his reaction.

He (it), stretches out his hand, calling for it to come to him. To get rid of the fire. To soothe the Mark. To make him not have to feel, again.

Cas pulls his hand away, breaking his connection with it. He tries to pull himself away from the Angel, again. He needs to get the Blade. To feel better. To feel like he's not ripping himself apart, from the inside.

He just wants to drive the Blade into the Angel's heart.

"Cas, go!" He feels like he's begging, now. He doesn't want to fight it anymore. He's done. He just doesn't want to hurt his friends, in the process.

"Stop this, Dean." Cas grabs onto his wrist, and doesn't let go.

He reaches for the blade again, and is again stopped by the Angel.

"Dean, why are you doing this?" He can't even bring himself to answer. He just keeps reaching for his weapon. Summoning it, with whatever sick powers it's given him.

It doesn't want him to be human. He can't ignore it, anymore.

"Answer me, Dean."

"Cas, move!" He yells. It feels like it's the first real words he's spoken in days.

"Why are you doing this?"

He can feel the Mark straining against his mind. It won't be fully unleashed, until he gets his hands on the Blade.

He doesn't know how to put this into words. How he has to let go. How he doesn't have a choice, anymore. How the Blade is all that he can think about.

"Cas," He says. "It's making me-"

He can't finish. Even without the Blade, the Mark's beating him. A goddamn brand is stronger than he is.

"You have to fight it, Dean." The way that Cas keeps repeating his name, almost feels like Cas is trying to remind him that he is, in fact, Dean Winchester. Or maybe trying to convince both of them.

"Why?"

"Because we're family. Family doesn't end in blood. Not spilt blood, Dean."

He's not listening, anymore. He can't. It's a miracle that he's held out this long. It feels like the Mark should have stopped him a long time ago. Unless-

"Get Sam out of here. Now," He says, urgently. Cas looks ready to fight him. "The Mark's playing us. It's stronger-"

And then the burning is gone. Replaced by the cool, welcome grip of the First Blade.

He can feel the euphoria rushing through him, as he plunges the Blade into Castiel's heart. As he sees the blood leak out onto the floor, ending all traces of family. Apparently family does end in spilt blood.

"S-stop, Dean." Castiel whispers, as it twists the weapon.

The grip on his wrist fades, along with the light in the Angels eyes. It's a calming sight to see.

He notices his brother ("Abel", the Mark whispers.) in the corner. The blood of his nose mixes with the blood of the Angel.

He's about to stab his brother's neck (doesn't even remember getting there), when he feels his arm halt in mid-swing.

The gates of Heaven are closed. If he kills Abel, he can't get to heaven. He'll have to wait. He'll come back when the Gates are open.

He has the faint thought that this can't be how possession feels. He feels like this is him. Like it's his feet walking out of the room. Like it's his whistle, cutting through the air.

He feels that way, until he steps on Castiel's dead arm, on his way out.

Then, he grins. This definitely isn't how possession feels.

This is how being Dean Winchester feels.

The new one. The improved one.