"The most obvious parallel is that Jon was resurrected from the dead, so he's a ghost in a literal sense," said Reddit user www_earthlings_com, referring back to season six when Melisandre brings Jon back to life after he's stabbed to death by his Night's Watch brothers. "Another interpretation is that ghosts tend to roam around the place where they died, or at the very least, they gravitate around it," the theory continues. Jon does just that when he returns to the Night's Watch at the end of season eight, haunting familiar grounds presumably for the rest of his days with Ghost right by his side.