The Hannibal TV show and prior Lecter movies featured villain Francis "The Tooth Fairy" Dolarhyde, who was sadly inspired by a real serial killer. While Dr. Hannibal Lecter became the clear star of Thomas Harris' literary world and its accompanying adaptations, he didn't start out that way. In Harris' first book, Red Dragon, Hannibal spends most of the story in the background, and is decidedly a supporting character. The same is true for The Silence of the Lambs, up until Hannibal's escape.
That's why it may surprise newer fans of the franchise that go back and read those books or watch those movies to see that Hannibal is by no means the main antagonist. In Red Dragon, it's Francis Dolarhyde, who seeks to eventually transform into The Great Red Dragon. In Silence of the Lambs, it's the Ted Bundy-esque Jame Gumb, aka Buffalo Bill, who skins his victims and then wears the trophies he's claimed. While Hannibal is most assuredly malevolent in his motives, he's nominally on the side of good, "assisting" Will Graham and Clarice Starling in their investigations into the new murderers.
Considering how much research Harris is known to have done into serial killer pathology before writing his books, it should come as no surprise that Francis Dolarhyde, like Buffalo Bill, also drew inspiration from a real psychopath or two. Which should serve as a constant, terrifying reminder that monsters like this aren't confined to fiction.
Hannibal: The Real Serial Killer That Inspired Francis Dolarhyde
As written in the book Red Dragon and its various adaptations, Francis Dolarhyde was loosely based on the BTK killer, an acronym for "bind, torture, kill." BTK was directly adapted recently for the Netflix series Mindhunter. His real name was Dennis Rader, and he claimed victims from 1974 to 1991, usually taking years-long breaks between his crimes. He was finally caught in 2005, ending a decades-long reign of terror. Like Dolarhyde, BTK enjoyed murdering entire families, and engaging in sex acts with his victims after the fact.
In letters to the police, BTK also claimed to be influenced by a supernatural force called Factor X, echoing Dolarhyde's compulsion to kill at the urging of his Red Dragon persona. Interestingly, Harris based Dolarhyde on BTK after consulting with John E. Douglas, legendary criminal profiler, who himself partially inspired the character of Jack Crawford. Douglas had worked on the BTK case, which was of course still far from being solved at the time of Red Dragon's publication, but was long-since over by the time Richard Armitage played Dolarhyde in Hannibal season 3.