What are you? Castiel is naturally an angel, but he is currently human at the moment. What makes him an angel, his grace, was cut out by an older siblings and the loss of their grace renders an angel human. Of course, a human angel isn't exactly human, and so he still has minor abilities beyond that of a normal human.
Do you exude some sort of supernatural energy or an aura? Castiel is a weird case. Most likely he does have some sort of supernatural air about him, but it isn't strong.
Would you like to not be noticed? It's up to you! It's totally fine to go either way. c: