After falling under the influence of the Mark of Cain, Dean is locked up in a dungeon while Sam and Castiel go looking for Gadreel. However, Dean escapes and embarks on his own mission to kill the Metatron. Unfortunately, the bout does not go in his favor and he is stabbed in the heart with an Angel blade. Before dying in Sam's arms, the elder Winchester tells his brother, "I'm proud of us." To this day, none of us have recovered from that moment. Dean is resurrected, but as the new Knight of Hell. Who saw that coming?
