Greater than Human
The boy, Nathaniel Zimmermann, discovered his taste for blood perhaps as early as seven years old. Only coincidences connect him to the horrifically mutilated animal carcasses that were always found six hundred sixty-six paces into the forest. Animals were found splayed open, organs neatly cut and dissected, eyes and mouths opened wide, illustrating the unspeakable pain in their last moments of life.
Nathan, on top of being a genius, also had incredible cunning. He kept his bloodlust under absolute control. He had no interest in friends, and he was spectacular at mimicking human emotion. He feigned a healthy contentment with life so that his parents wouldn't get suspicious.
Nathan graduated medical school with top honors, and decided to become a surgeon. His handiwork was precise and efficient. His surgeries often ended in record time. Then his cover was blown.
Nathan's sadism was eventually exposed. It was discovered that in addition to tampering with anesthetics (explaining his absolute contempt towards anesthesiologists), he sometimes replaced a person's painkillers with snake venom.
Nathan's medical license was revoked, but he found his niche in being a torturer-for-hire.
His only stipulation was that the victim was to die immediately following the torture, as any pain they felt after the torture would be almost pleasurable. Nathan so hated when people felt happy.
Nathan has murdered countless people, almost always torturing them first. It is rumored that when one of his victims was unable to feel pain, he simply started cutting off her extremities until she was immobile, then he shoved a screwdriver through her skull.
Oddly, it is not known whether he is a virgin. His arrogance seems to preclude him from any sexual contact, as he considers himself greater than a human. What is frightening is that he may very well be right.