The first time, Castiel had been sick.
His vessel, Jimmy, remembered the sensation of vomiting, and recoiled against Castiel's agony. No.
But Castiel was kneeling in his best friend's blood, his hands stained with it, the angel sword buried in Dean's chest and he couldn't-
And then he was heaving, coughing and choking and sobbing, pounding his hands against the ground of the warehouse calling Dean's name out between coughs, over and over and over-
"That's enough, Castiel." Naomi's cool voice cut through him, straight to the bone, and suddenly he was back in the white room again.
"I can't hurt Dean," He'd whispered, aware of how small and weak his voice sounded and not caring at all.
"You can," She said, still with that maddening calm, "and you will."
The second time, Naomi had to grip his hands and force the angel blade down.
Dean and Castiel had screamed as one. But then Dean had fallen silent and it was just Cas, gripping his head and falling to his knees, screaming, his wings folding around himself, Jimmy shouting mindless words of protest inside of him. His vessel knew what to do because Naomi was training Jimmy just as much as Cas. The difference was that Jimmy did not care quite as much.
"Pull yourself together, Castiel," Naomi has snapped, and had yanked him upright by the back of his trench coat. "I'm trying to help you."
The third time, Castiel had cried.
He'd sobbed, broken, rasping sobs as he stabbed the blade into his friend's chest. Sobbed, as Dean fell to the ground. Sobbed as the blood spread around him, hot and wet against Cas's shaking hands.
Naomi had not said anything. She's simply pulled him to his feet and pressed the blood-soaked weapon into his hands.
The fourth time, Castiel hadn't said anything.
He'd stabbed Dean in the chest just like they'd practiced the other three times. He'd watched his friend fall.
And then something inside him had snapped. His knees had crumpled out from under him and suddenly he was on the ground, face pressed to Dean's chest as if he could will him back to life, wings folding protectively over both of them. He'd lain their and whispered pointless words in enochian, recited prayers and old songs from Earth that Dean would have loved.
Naomi had growled something and yanked him away from Dean. He'd twisted and fought her grip but she gripped his chin, hard. "You. Will. Do. This."
And he'd been hurtled back into the warehouse with a fresh angel blade and her voice pounding orders in his mind.
The fifth time, Castiel had refused.
He'd dropped the weapon, curled up on the ground and prayed to his Father, screamed for him to make this stop.
Naomi had wrapped his fingers around her own angel blade and forced him to stab Dean in the chest, over and over and over until his vessel was sprayed with blood.
Castiel didn't stop praying or screaming the entire time.
The sixth time, Castiel had apologized.
"I'm sorry, I'm sorry, I'm sorry," He'd cried over and over as Dean neared him. Stabbing the blade into his friend's chest the words came out in a scream, "I'm so sorry, Dean!"
Naomi had smiled at him. "I'm sure he forgives you, Castiel."
Castiel had only pulled the blade from Dean's sixth corpse and thrown it across the room with another cry.
The seventh time, Castiel had held Dean as he'd died.
He'd cradled the hunter in his arms and prayed with him. Held him close as Jimmy had once held his daughter. His vessel was screaming at him that this wasn't right, that they should be doing what Naomi asked. Castiel ignored him.
Bowing his head to Dean's still chest, Castiel silently cursed himself, Naomi and heaven for allowing this to happen.
It shouldn't have to be this way.
The eighth time, Naomi had to help him again.
He'd been shaking so much that he couldn't even raise the blade. Naomi had pushed Dean into the sword this time, so Castiel could feel the weight of human flesh against him, she'd said.
All Cas saw was his friend's dead eyes and the blood that was so red against his shirt.
The ninth time, Naomi made him break Dean's wrist before he killed him.
The action had been simple, but the feeling of his friend's bones cracking under his hands had made Castiel fall to his knees again.
Dean had screamed, but it was Naomi's harsh words that Castiel heard.
"You are weak, Castiel. Kill. Him."
Jimmy had suddenly taken control, and did the job for both of them.
"Your vessel knows what to do, Castiel. Maybe you should listen to him."
The tenth time, Castiel had done it quickly.
Before he had time to scream or break down, or even think about what he was doing, he'd stabbed his friend in the chest and Dean was dead.
Naomi had clapped her hands, as if watching a particularly entertaining play. "We're going to have to make this more challenging for you."
So she made Dean scream and beg, every time after that.
It had taken one thousand times to break him.
By the end of it he only felt numb. He was a machine, reacting to commands. He moved quickly and efficiently while Dean begged. When his friend pleaded with him, he didn't listen.
After his thousandth kill, Naomi had smiled at him. "You're ready."
What Castiel didn't realize was that he really wasn't.
"This isn't you, Cas," the words Dean spat out were through a mouthful of blood, but they reverberated through his being.
This isn't you.
No, it wasn't. This wasn't Cas. This was Castiel, the good soldier, Naomi's puppet.
But he couldn't stop.
He was breaking Dean's arm with lightening speed, hitting him in the face over and over and over-
Just like they'd practiced.
"This isn't you!"
It wasn't, it wasn't it wasn't-
'Cas! Cas please, Cas-"
Cas, Cas, Cas...
His hand slammed down again, breaking Dean's nose. Cartilage crunched under his fist.
Dean was on his knees now, weakly reaching up to grasp Castiel's arm, protesting, begging...
"We need you. I need you. We're family."
Castiel raised the blade.
Cas, buddy, I need you.
Sorry, but I'd rather have you. Cursed or not.
I need you.
I . Need. You.
With a sharp snap, Castiel broke free from Naomi's tugging puppet strings. He gasped. The angel blade fell from his grasp and he released Dean's wrist.
He hardly heard the sharp, rasping sound of the hunter's breaths as Dean slumped back in relief. He could only hear the harsh pounding of Jimmy's heart, racing against his ribcage. He felt only the aching tear of his wings, expanding out behind his back.
He would not be Castiel any longer. Castiel did not need Dean. Castiel did not serve man. Castiel was a soldier. He would not be that right now.
He would be Cas.
Because that was who Dean needed him to be.