You may have thought that villains and killers are just found in horror and action movies, but guess what, there are some who actually lived here on Earth. There are many people who kept asking how can they actually kill someone without thinking that those people whom they've killed will eventually haunt them in their conscience. Here's a thing: according to Psychology those who kill may have already lost their sanity, therefore they cannot anymore control every thing they do. Here is a list of serial killers and their profiles:
Doctor Harold Shipman

His real name is Harold Frederick Shipman. He is the most prolific known serial killer in British history, and possibly the world. 215 murders are ascribed to him, though the real number may be much higher. At the end of the investigation, they found out that the real number of deaths could be up to 250. They discovered a pattern of his administering lethal overdoses of diamorphine, signing patients' death certificates, and then forging medical records indicating they had been in poor health. What was very intriguing is that his colleagues did not even report this questionable number of deaths. He committed suicide the day before his birthday at the age of 57 years old.
Luis Garavito

He is a convicted killer and rapist who have been called by the media as the "worst serial killer". He admitted that he had killed and raped a number of 140 young boys. The victims were poor children, peasant children, or street children, between the ages of 6 and 16. Garavito approached them on the street or countryside and offered them gifts or small amounts of money. After gaining their trust, he took the children for a walk and when they got tired, he would take advantage of them. He then raped them, cut their throats, and usually dismembered their corpses. Most corpses showed signs of torture. He was guilty of 138 murder cases, and if totaled his life imprisonement should have been at least 1,853 years and 9 days, but was later reduced because of Colombian rule restriction. Many people argued whether the court decision was justifiable.
Thug Behram
He was a leader of a cult known as the "Thuggee cult" which believed in human sacrifices. Although there are only 125 identified murders, it is said that he may have killed 931 giving him the title as "the most prolific serial killer of all time". Victims were strangled using his cult’s ceremonial cloth, rumal, the Hindi term for handkerchief. Behram was late executed in the year 1840 by means of hanging.
Pedro Alonso Lopez

He is alleged of killing 300 girls. His anger all started when he was evicted from his family after he was caught caressing her sister by his prostitute mother. He had been caught by a native tribe, who were preparing to execute him, when an American missionary intervened and persuaded them to hand him over to the state police. The police soon released him. He relocated to Colombia and later Ecuador, killing about three girls a week. López later said "I like the girls in Ecuador, they are more gentle and trusting, more innocent." He is convicted to life imprisonement and until now he is still in prison.
Javed Iqbal

In the year 1999, he wrote a letter to the police stating that he killed a total number of 100 boys fro ages 6 to 16 years old. They were all runaways from orphanages. Mostly of his victims' bodies were dissolved in a container with a concentrated solution of Hydrochloric acid. What was very strange was it is as if that it was his intention for the police to find out his crimes.
Yang Xinhai

He is part of a very poor family in China. He dropped out from school and never went back to his family. Yang's killings took place between 1999 and 2003 in the provinces of Anhui, Hebei, Henan and Shandong. At night, he would enter his victims' homes, and kill all of the occupants—mainly farmers—with axes, hammers and shovels, sometimes killing entire families. Each time he wore new clothes and large shoes. He did not really tell his motives for killing people but you will really be intrigued with his statement: "When I killed people I had a desire (to kill more). This inspired me to kill more. I don't care whether they deserve to live or not. It is none of my concern...I have no desire to be part of society. Society is not my concern." He was sentenced to death on February 14, 2004.