(You’re safe! No grossness or spoilers; just PA over-analyzing the obvious.)
Hannibal Lecter in his various guises belongs, I think, in the Hall of Fame of the classic literary monsters. He has more in common with Dracula or Mr Hyde than he does with slasher film villains or torture porn. But he reminds me most of Frankenstein.
There are three forces at work in a classic monster horror story: the human, the alien, and the monstrous. It’s like a recipe; each of the three can stand alone, but in a more sophisticated story, they get blended in varying degrees and combinations.
In a traditional monster story, the monstrosity and alienness tend to get separated out from the human and put in the bad guy/critter. And there’s something comforting in that, even if it’s a horror story: we’re telling ourselves that the monster is the alien; it’s not us. Humans (at least ones who’re functioning ‘properly’) are neither shunnably different, nor evil.
But Mary Shelley blurred that line (ironically, before most of the other famous monster stories were ever even written). It was hard to decide, in the novel, whether Victor Frankenstein or his Monster was the real monster, when it was Frankenstein’s obsession, callousness and self-absorption that led him to twist the initially innocent life he’d created and set its feet on the path it ended up following.
Hannibal—the character and the series—entirely drops the comforting illusion. Most of the characters are some combination of the three. All are entirely human; most are Othered in some way, through their talents or jobs or psychologies or illnesses; many tread into the territory of the monstrous, having done terrible things or possessing an ability to comprehend monsters to a disturbing degree or demonstrating a willingness for moral compromise for the sake of their goals. And like some sort of horrible atomic clock, Hannibal sets the standard for them all. He’s the archetype of monstrous horror for the 21st century; he’s the monster when the monster is human.