 When the Winchesters unintentionally change history when a wish-granting pearl draws John Winchester of 2003 into the present, this creates a new timeline where Castiel is still a servant of Heaven alongside Zachariah.The Winchesters are able to kill Zachariah and banish Castiel, but eventually are forced to send John back to restore the original history.Michael is eventually destroyed when Jack taps his remaining powers, but this results in damage to Jack's soul, with the Winchesters and Castiel becoming increasingly concerned about his future sanity.