We have casting news for season 13.
From EW Supernatural: Alexander Calvert upped to series regular for season 13.
So Lucifer's son, Jack will be a fairly important player next season. We don't have much more information than the fact that he is a series regular. We will update when more information becomes available. What do you think about Jack becoming a regular? Tell us in the comments or in the discussion thread for season 13.