Castiel moves into the room, feeling the sigils push against him, even as he's allowed through. He hesitates for a moment before sitting stiffly at the foot of Dean's bed, turning to face Dean.

"Crowley is dead." He meets Dean's eyes. "I killed him."

There's no real guilt. Castiel doesn't like ending lives and Meg has made him reevaluate his stance on demons, but Crowley's done so much to hurt the people he cares about. Crowley tried to turn him against Dean. Attacking Meg had been the last straw.