'Supernatural' Season 9 Introduces New Demon Cain / Retired Knight of Hell Debuts in Upcoming Episode "First Born"

The cast of Supernatural Season 9 welcomes a new demon named Cain to the bunch.

In an upcoming episode titled "First Born" fans will get their first glimpse at a demon named Cain, who was known, before retiring, as the Father of Murder. He was in charge of training the Knights of Hell.

But what is Cain's relationship to Abaddon, whom we thought was the last Knight of Hell. We don't know much about Abaddon. As of now we know she wants to overthrow Crowley, and become the new master of Hell.

We know she planned a 1950s attack on the Men of Letters. She transported to the present day to kill Henry Winchester. She was then destroyed by Sam and Dean. She's now back to take the throne of Hell from Crowley and return the world to nightmare status.

With the introduction of Cain, we can probably infer that he trained Abaddon. Is she his love interest? Is she the reason he's now back in the game?

Will he help Dean and Sam track her down with a little insider information?

Tune in fo Supernatural, which airs Tuesdays at 9 PM on The CW.