Kate Bishop and Castiel
"No more jealous than my dancing with you makes him," Castiel said, smiling slightly. "I love him, I always have. I know that he wouldn't do anything beyond flirt with the server." Unless he asked for Castiel's permission first. And even if Castiel gave said permission, he wasn't sure Balthazar would do anything beyond flirt.
He nodded, "Yes." It was simple enough. He would protect anyone who called out to him, anyone who needed his help. All they had to do was alert him to the fact that they were in danger and needed his help.
"Unless it's just about whether you can't decide between Chinese or pizza for dinner," he said, smiling slightly.