Hannibal Lecter, M.D., a.k.a. "Hannibal the Cannibal", is a serial killer created by Thomas Harris, and the primary antagonist in the series of his actions opposite the FBI and other law enforcement that either consult or attempt to capture him.
Losing his entire family to the horrors of World War II, young Hannibal eventually started to kill as a method of avenging his younger sister, until all trace of his humanity was gone, replaced with a genius level intellect and a hunger for human flesh. Despite this, Hannibal is also an astute psychologist, both advising and manipulating FBI agents Will Graham and Clarice Starling to his own ends.
Even from the confines of a mental institution, Hannibal possesses keen psychological insights into the suspect the FBI seeks, even though his actions often endanger the same agents going to him for assistance with his manipulation of their thoughts and emotions.