Ed Kemper. He skullf*cked his mother’s severed head.-u/heirkenndifnrbahosk

Albert Fish. He was a serial killer who would kidnap children, torture them, molest them, kill them, eat them afterwords, and send letters to their parents describing how they tasted. Not a nice guy 0/10.-u/Bobglobslob

Jim Jones, ordered a mass murder-suicide that claimed the lives of 909 commune members, 304 of them children.-u/SuvenPan

Georgia Tann. She ran the Tennessee Children's Home Society and helped a lot of Hollywood stars adopt babies. In order to keep up with demand, she would train people to pose as nurses and they would steal newborns, telling the mothers their baby had died. She and her employees also used threats of legal action to procure children, they would go to nursery schools posing as welfare agents in order to kidnap children, and they would adopt out children who were only supposed to be in the children's home temporarily.

While in her care, Tann mistreated her charges and there are reports of murder through neglect. She would use bribes to get away with it but eventually, the law caught up with her and the Children's Home Society was closed in 1950. She died of uterine cancer, the same year the home was closed. I sincerely hope she suffered.-u/Applesintheorchard

Jeffrey Dahmer, f*cker injected hydrochloric acid into a little boy's brain and kept him alive for a day or something. He injected another dose into his brain again and the kid died. This is just one of his 17 murders.-u/nonamesuperhero

I would call the “people” who tortured Junko Furuta to death pieces of sh*t, but at least sh*t has value as a fertilizer.-u/ABB0TTR0N1X

King Leopold II, what he did in Congo was absolutely heinous and devilish.-u/benboy952

Anders Behring Breivik definitely takes the cake for me. Blew up a bomb in the center of Oslo. Meanwhile went to an island where a political youth gathering was taking place. Dressed up as a cop, he would kill 69 people on the island Utøya, and call out to teenagers hiding saying it was safe to come out, those who believed his costume were shot.-u/Eremitic23

Pol Pot. I only recently visited Cambodia and learned of this man. What an evil, disgusting Soul he was.-u/Altruistic-Dentist41

Israel Keyes. Dude picked people at random to kill and planned it months in advance. Would travel to places and hide a "kill bucket" and come back months later to kill.-u/wigginsadam80

Paul Bernardo. His pride in his evil and his utter lack of concern about anyone else are seared into my brain after reading a book about him.-u/Smileinstead

Heinrich Himmler. Himmler was responsible for conceiving and implementing the Holocaust. He also made sure that the death trains ran on time and that the camps adhered to strict standards of murderous efficiency. Yeah. Psycho.-u/ihycsailor

Those Japanese soldiers who made "Comfort Women" and used women as sex slaves, and tortured them when they ran away. A prisoner who tried to run was tattooed, tortured, or killed. In one case, a head was severed and boiled, and the soldiers made some of the other slaves drink the liquid.

And the cover-ups thereafter - how these women were prostitutes, how these men didn't exist. As if. And recently, some group made these women into figures and mocked them in disgusting ways.-u/Moomting

Oskar Dirlewanger, the guy managed to get fired from a concentration camp for mistreatment of prisoners.-u/Ukrainian_Tractor07

Joseph Mengele. He would choose twins to experiment on and would cut one open with no anesthesia to see if the other one would feel any pain. Eva Kor was one of his victims and her twin sister Miriam passed away many years ago due to issues caused by Mengele (her kidneys had stopped growing while at Auschwitz due to injections given to her and she died from kidney cancer). Eva only passed away in 2019 while accompanying a group to Auschwitz.-u/Kuchenkrusher

The one that comes to mind is Rodney Alcala. The dating game killer. He's pretty messed up. I highly recommend listening to the last podcast on the left episodes about him. Grim but fascinating stuff.-u/Chaotic_Gayboyy

Ed Gein, he made furniture out of people.-u/wisconsinking

Not sure the biggest, but Lainz angels of death are up there. Maria Gruber, Irene Leidolf, Stephanija Meyer, and Waltraud Wagner were four Austrian women who worked as nurse's aides at the Geriatriezentrum am Wienerwald in Lainz, Vienna, and who murdered scores of patients between 1983 and 1989. The group killed their victims with overdoses of morphine or by forcing water into the lungs.-u/Sorry_Deer_4162

Genghis Khan. He once ordered an entire city razed and the heads of its citizens stacked into a pyramid. All because his ambassador was "insulted."-u/Medieval-Mind

Ted Bundy, he was pure evil yet still able to control his actions in a sophisticated enough manner to go undetected for years. When he wasn’t raping and mutilating dead corpses he was just a normal guy walking among the people.-u/JAMeyer04

The entire Japanese military in World War 2. Some of the shit they did was absolutely horrific. Bataan Death March, Unit 731 experimental facility, Burma railway construction, Sook Ching massacre, Changjiao Massacre, and Pearl Harbor just to name a handful.Mass rape, public execution, the slaughter of civilians, horrible treatment of POWs, the Japanese in ww2 committed atrocities comparable to Nazi Germany.-u/True_85

Elizabeth Bathory. Hungarian noblewoman who murdered over 600 young women (most of whom were servants) during the 16th century. It is said that she killed them for their blood, as she believed that it would help her keep her young. If repeatedly killing young women for their blood until the victim count reaches over 600 doesn't make you a massive f*cking psychopath, I don't know what does.-u/Melon-Kolly

Nightstalker / Richard Ramirez - This man had no MO's as far as how he chose his victims...normally these guys like Ed Kemper only go after one type of person like young females because of their childhood / being degraded by their mother...not Rich...he would pick any type of household just sneak in and beat you and your family to death while you were sleeping.-u/wtfisgoenon

Mao. Dude killed over 80 million of his own people.-u/CerebrumMedicus

Vlad Tepes, better known as "the Impaler," or "Dracula," who used to eat while hearing the tortured moans of his victims as they slowly died on spikes; to ensure the Turks refused to attack, he captured an entire army and impaled them along the route into Transylvania.-u/Medieval-Mind