It takes everything in Castiel not to strike Benny down.
To see Dean working with something as lowly as a vampire has his skin crawling. Worse the way the two so easily work and talk with one another - it has him feeling something he had not felt in a while;
Jealousy.
Smug pride swells in his chest when Dean dismisses Benny. It's almost a feeling of 'yes, that's my Dean. Not yours, mine.'
Then the moment comes when Benny saves Castiel's life. Despite how both hunter and angel treat him, or how he knows the angel is holding them back, that they can't get him through.
He saves him.
From then on something clicks and Cas watches with new eyes.
Dean curls against the vampires chest as they rest. Both need sleep but Cas doesn't so he just watches. Happily at that.
He moves over, brushing Dean's hair back and catching Benny watching him.
For a moment he thinks that he doesn't mind sharing if Benny keeps looking at Dean like that.
Like he's precious.