 Despite this, Castiel is eventually captured by Naomi's forces, but the angel tablet is claimed by Crowley after one of Naomi's angels betrays their location, although this gives Castiel time to escape and reunite with the Winchesters after killing the angel guarding him.With Heaven in chaos, Metatron (the Scribe of God, recently rediscovered) convinces Castiel that they must seal the gates of Heaven to force the angels together to make peace.The first trial is to cut out the heart of a nephilim, the child of a human and an angel, which Castiel is forced to kill when the selected target attacks him.