You were a witch, alive for a quite a long time(or short time, you chose). You had seen a lot through your years including an angel. And not in the sense that they acted like a saint, as in kind, as in the figure of speech. A real angel, with wings and angelic powers, a soldier of HEAVEN, a messenger for God. It blew your fucking mind. He explained to you that you had a very important place in the future, he never told you why though, but he helped you manage your abilities after explaining you had natural abilities which did kinda make sense to you after years of being different and seeing things others couldn't.

Eventually he introduced you to his other friends, Dean, Sam, and Bobby. You could feel the sexual tension between Cas and Dean but never brought it up. Then one day..

Cas zapped into your house while you sat doing whatever, "I need help." he spoke in that same stotic tone which made you jump since you hand heard him come in "I need you to teach me about how to understand others."