One

You are an immortal being, not limited to a species because even the Archangels have no idea what you are. Your only friend is Castiel, when he has time to visit. Even though you are over 6 million years old, you have very little control over your powers, so you stay inside to protect the humans from you. Then Castiel lets you meet the Winchesters, and your new life begins.

I don't own Supernatural or any of the characters though I wish I did.