Pop culture has no end, especially when it comes to adoring fictional characters. Some take on a life of their own and go beyond a creator's wildest dreams. It's a common phenomenon that TV audiences are all too familiar with in a world of 24/7 streaming. The thought of losing a beloved character to a heartbreaking death is more than some fans can handle. But certain characters seem tailor-made to circumvent that fear, and they all have one thing in common: immortality.