The scariest ones dor me are probably Richard Lake and Charles Ng, The toybox killer, Robert Pickton and Dean Corll
Pickton is just an incredibly gruesome story, his whole live was disgusting and its one of those cases were is an entire community, no fucking way no one else knew that something fucked up was up at that pig farm. .
the other three are terrifying because it wasn't just killing someone , but restraining and videotaping them for long periods of time for all sorts of torture. In the case of the toybox i remember reading how a ton of hillbillies knew the family had drugged sex slaves and they participated in the torture, they even raped them at parties or watch as dogs fucked the women while they all had a beer. The tape transcripts and the photos of the sex dungeon are nightmare fuel. With Dean Corrl theres also the element of many people being accomplises, kids were turning in other kids for rape and torture, the concept of it happening in broad daylight for so long with that many people around actually getting used to it is nuts.Richard Lake and Charles NG are mongoloids, straight up clowns, makes the horrible situation the victims endured even worse, this is what truly does it for me.
Richard Ramirez was scary because of how mad and random he seemed. Most of the times he was oportunistic and went totally chaotic, he was always on drugs and really couldn't care less for anything, a wild beast with nothing inside.
What i can say in general about serial killers is that most of them are very boring people. Outside of killing they are pathetic, with little to none personality , no big ideals or nothing, no draculas or Hannibal Lecters, like seriously most are on the verge of unironic retardation . The cliche of the genius killer who fools everyone and makes it an artform is just a meme, most are not that calculating beyond something any random person can come up with to get away with crime , the only diference is most people will never actually want to commit those crimes, What makes them special is that they have these urges and they simply don't give a shit, only certain individuals can have such degeneracy mixed with an extreme lack of empathy, even mobsters and soldiers who kill have a justification other than "muh dick hard, don't care", even jamaal in the hood who will shoot up a rival gang is not as purposeless or nihilistic. Authorities are pretty fucking pathetic in almost every serial killer case, is very difficult to even link these types of cases, even when everything is doing their job its still a matter of luck since legit these types of crimes are difficult to pick up. Maybe nowadays is harder for a serial killer thanks to technology and how everyone is tracked all the time but they are still out there, in countries that are not as developed in criminalistics who fucking knows, theres many loose at any given time in the first world.