"Dean, I never asked you to risk this much for… for me!"
"Cas. Cas, I want to!"
The angel looked horrified.
"Look, Cas. You've saved my ass more times than I can count. Why can't I return the favor?"
Cas could see the set look in Dean's eyes and knew he was too stubborn to give up, but he didn't know what he was saying. How could he?
"I'm not dying. You wouldn't be risking your life and sacrificing… everything to save my life, because it's not in jeopardy. If you died, it would be in vain. And I will not let that happen."
Dean was having none of it. "No. You know what? Your life is in danger. You're falling, right?" The angel's curt nod answered Dean, even if he could no longer meet Dean's gaze. "And if you fall and become human, eventually, you'll die."
It wasn't a question, but Cas answered Dean anyway. "It is one of the more regrettable consequences of being human, yes."
Castiel finally looked straight into Dean's eyes as he felt a reassuring hand on his shoulder. The way a single touch could pull at his heart was astounding, as if Dean was a magnet that positively corresponded with the angel's negative emotions and ripped them out of his grace.
"Cas, I'm gonna point something out to you. You've pulled me from Hell, saved me a hell of a lotta times on Earth, helped us fight against your own dick brothers, and I'm pretty sure I made it out of purgatory because of Benny and you." Dean held up four fingers for Cas to count. "Has anyone else done as much as you have for me… in four different realms?"
Castiel just stared. He didn't know what else he could do. How on Earth, (or in Heaven, Hell, or Purgatory,) could he convince Dean to have a shred of self-preservation? His last resort was Dean's main weakness, his Achilles heel. Cas sighed as he turned away. "What about Sam?"
The reassuring hand turned stiff and disappeared from the angel's shoulder. "What do you mean?"
"When you went to hell in exchange for you brother's life, and when you were with Lisa while Sam was hunting with Samuel, and when you were in Purgatory… Sam was alone. He turned to people like Ruby and Samuel, because his brother wasn't there. You weren't there, Dean, and look what it did to Sam. Everytime." The haunted silence Dean was keeping told Castiel he was on the right track. He knew if he turned around, the hunter would be staring at the ground, eyes glazed over in disbelief. Don't stop now. Kick him while he's down. He'll listen if it endangers Sam. Even if he won't listen to Castiel's wishes. "How could you abandon your brother yet again, for something that's not even worth it?"
Dean looked up at his angel's last words. He'd had him, too. God, did he have him, right up to the last part. Dean knew that Sam was a major factor when it came to making up his mind on something, and it was pretty goddamn obvious that all the demons, angels, monsters, and everyone one else knew it, too. And, yeah, it was pretty low for Cas to try and win by using Sammy, and Dean understood hurting someone to push them away. He was pretty much the king of using that tactic. But Cas had given himself away. He wasn't concerned about the younger Winchester, not really. "You're not a something, Cas. You're someone. And you are worth it. Well, I think so anyway." Castiel heard heavy footsteps leading away from him before he had the courage to turn around. He had wanted to see Dean's face, the oh-so human expression that was upon it, but he was too late. That must be a pattern in his life.