After a while it becomes a default setting.

The way his blade became almost a natural extension of his arm, how his ears were attuned to the slightest sound, his whole body able to feel the tiniest of shifts in air pressure.

How long had he been running himself in this adrenaline soaked state?

It was hard to tell.

Could be hours.

Could be years.

Sometimes he seemed to be permanently running, like a prey animal, all watchful eyes and held breath.

Other days though, he was all apex predator. Stalking, silent, ready to strike.

Perhaps if he could just pick, make the choice.

Predator or prey.

But it was more complicated than that.

With his back to the dark barked tree, Dean stilled his heart, breathing long and slow, making himself as silent as possible.

He ran his tongue across his upper lips.

Tasted the salt of sweat, the harsh copper of old blood, and something else. A bitter, earthy taste he couldn't identify and truthfully didn't want to.

He glanced across the clearing at Cas and Benny.

Sometimes he was glad to have them here, watching his back.

But other times, like now, he wanted to be alone.

He wanted the kill all to himself.

Was greedy for it.

Wanted to bathe in the aftermath of blood and fear.

Vamps.

Easy.

He saw Benny stiffen and Dean wondered, not for the first time, if this would be the day he switched sides. If Benny would turn on him and Cas, rip their throats out.

No time to dwell on that now.

Swiftly he drew back his arm, and in one fluid movement, stepped away from the tree and swung the blade into the face of the first vamp.

So many of them.

They were drawn to him, the only human in purgatory and now it seemed as though there were waves of them, all hell bent on one thing.

Kill him.

Kill the angel.

Kill them all.

Fuck that.

He hacked and slashed with brutal accuracy, constantly moving forwards, pushing through the vamps that seemed to lose any semblance of humanity and self preservation they might have once had.

The longer you stayed in purgatory, the more animal like you became.

He swung the blade in a long arc, removing one vamps head before thrusting it backwards into the gut of another.

Sometimes, when it got like this, he almost felt like he was becoming the monster, that mothers would tuck their children into bed at night with a warning to behave or Dean Winchester will come get you…..

He liked that thought.

With a low growl he sprinted up the side of a bank towards a group of stragglers, newer souls perhaps, they were trying to run anyway.

He grabbed the nearest by it's jacket, his fingers clamping down, vice like, on it and dragging it to the floor.

It's fangs retracted and it held up it's hands, eye's wide and moist, shaking in fear.

"Please!…."

But it didn't get any further.

Dean brought the blade down across it's throat, severing the head.

Then he started to stab it, slamming the blade again and again into the jerking corpse, twisting it, hacking, slashing, pulling it through the chest cavity until his forearms were slick with blood, his bone white face splattered with gore.

Hands on his arms pulled him away and he spun violently to face them.

Cas and Benny stood watching him. The angel calmly, but with a terrible, twisted sadness in his gaze, Benny fearfully, his stance low, hands half raised.

"Easy there brother….. It's over. They're gone…"

His eyes flicked from Deans face to the blade and back again.

Dean took a deep breath, relishing the tang of death, the stillness of the forest, the light steam rising from the corpse behind him.

"I'm fine." He muttered, stepping forwards to pass them.

"Dean…." Cas lay his hand on Dean's shoulder.

Angrily he shrugged it off.

"I'm fine."

They didn't follow immediately, and he was glad. Because he wanted to kill, and they where the only things left with blood in their veins and God but he wanted to.

He held his hands up to his face, inhaled the scent of blood and knew only one thing.

He wanted this.

The blood and the death and the hunt.

It was who he was.