The synopsis for penultimate episode of Supernatural.
 
Inherit The Earth
 
CARRY ON – Everything is on the line as the battle against God (guest star Rob Benedict) continues. A familiar face returns to join the fight. The episode was directed by John Showalter and written by Eugenie Ross-Leming & Brad Buckner (#1519). Original airdate 11/12/2020.

Source:

CW

 
The battle against God, the ultimate opponent. Who is the familiar face that returns to help? How will this end? Let us know in the comments or in the discussion thread for episode 19.