Sam didn't mean for it to happen at all, it just had.
Some might have called it heat of the moment but he called it being down right careless. They had been caught up in a trap of sorts. The angels had wanted information that only Castiel had and the only way to get the angel of Thursday was to get through Sam and Dean
The angels had been extremely quiet lately, so much so that Cas had given them an angel blade each from other brothers and sisters he had killed in the past. Castiel had said it was for their protection and the greater cause or whatever that meant. Sam just thought he was afraid.
Castiel told them they had to be ready for anything. So when a month, then two going on three had passed they all became lax, wrapped up in other jobs, hunts and day to day chores.
Sam did his usual research.
Cas dealt with himself slowly becoming human.
And Dean pampered his baby.
That's when the angels decided to attack.
The three of them were away from each other when it happened, each holding their own everyone yelling out the others names to see if they were okay. Sam let his auto pilot take over, striking any unfriendly face while dodging and weaving like a true hunter.
There was still no sign of Dean and Cas.
A hand grabbing his shoulder was more than enough for Sam to stab the blade back between his left arm and side, through to the chest behind him.
Three down, there couldn't be many to go now surely.
When the hand didn't leave his shoulder, the uneasiness settled in and that's when Sam turned to look.
Colour drained from his face as he looked at the mop of black hair.
Castiel was looking down at the hilt of the angel blade sticking out of his chest, light already slowly pouring out of the wound and wisps flowing from his mouth like blood. His grip on Sam's shoulder tightened and he slowly started to slump down to his knees.
Dean came running round the corner out of breath and froze, pure shock written on his face. His eyes followed Cas' every move as he slid to the floor.
"Cas?..." The elder Winchester mumbled as he ran to his angel's side. "Oh no..no no please!" He begged, falling to his knees. He pulled the angel to his own chest and turned his face up so they were looking at each other.
Tears were falling from the crystal blue eyes as Castiel looked up at Dean, he was afraid to die. To no longer be able to look upon the righteous man's face, to never gaze into his ever green eyes again.
He would miss that greatly.
Castiel reached up and traced his fingers along Deans cheek and down towards his jaw, mapping out as much as he could before his last scrap of grace burned up. Dean was talking to him now and Sam was saying something as well but it was too late.
"I forgive you Sam…" Castiel mumbled, glancing up at the tall Winchester. Sam was leaning heavily against the table behind him crying, tears pouring down his face.
Cas looked back up at Dean and smiled sadly.
"I love you so much Dean. You were worth being saved...Please don't forget that."
"I-I love you too man…" Dean lent down and pressed his lips against Cas' forehead.
The light was blinding when his angel died.
The silence was suffocating after the light disappeared. Dean and Sam looked around and saw the scorch marks of their friends' wings along the floor, one tracing up the side of the wall and partly on Deans right arm.
"He loved you…." Sam croaked, standing in front of his brother.
"Yeah, that's what he said." Dean didn't look up.
"…Do you really love him too?"
Dean was silent for a while, looking down at the man in his arms. He traced his fingers all over the face of his best friend, wiping off the tears that were fresh and old.
"Probably not in the way he wanted me to…"