 When the angel Durmah attempts to establish a more ruthless form of Heaven, Castiel kills her when she tries to use John and Mary's souls as a blackmail tool.God eventually returns to offer the Winchesters help against Jack's corrupted state, but when the Winchesters realize that God is manipulating the situation to suit his own narrative aspirations, they reject his plans, prompting God to release all the spirits and monsters the Winchesters have previously defeated from Hell.The Winchesters are able to defeat the wave of monsters after Rowena sacrifices herself to take the spirits back to Hell, but with his powers weakening and Dean blaming Castiel for Mary's death, Castiel decides to move on, although an encounter with a djinn inspires Castiel to continue trying to help others.