jack was the only Nephilin son of Lucifer and a human, but you were also a nephilin also son of Lucifer, but no one knew about your existence because your demonic side didn't awaken, which made you become unknown to everyone until. .. however in an anxiety attack while you were at school, your powers awakened causing everything and everyone around you to die or disappear. When this event became known, Dean and Sam went to investigate and it didn't take long for them to find you.

they tied you to a chair and threw salt on you thinking you were a demon but neither salt nor holy water nor any of these things worked

dean: what are you? before you could respond castiel appeared and said castiel: a Nephilim...