* Scorpio (The Scorpio Killer): The main antagonist in the first film, "Dirty Harry," this killer is a serial sniper who terrorizes San Francisco. He is known for his elaborate taunts and his cryptic messages to the police.
* The Red-haired Detective (The Killer): This killer is the main antagonist in "Magnum Force." He is a corrupt police detective who believes in killing criminals, even if they haven't committed a crime yet. He is responsible for a string of murders, and Callahan is tasked with bringing him to justice.
* The "Big" One (The Terrorist): The main antagonist in "Sudden Impact," this killer is a former San Francisco police officer who is seeking revenge against the city for an incident that happened in his past. He is responsible for a series of violent crimes, including a shooting rampage at a beach.
* The "Death Wish" Killer (The Degenerate): This killer is the main antagonist in "The Dead Pool." He is a private investigator who becomes obsessed with Callahan and attempts to frame him for murder. He is responsible for a series of murders, all of whom are listed as "death wishes" in a book by a psychic.
While these are the main antagonists, Callahan has also encountered and pursued many other criminals throughout the series.
Is there a specific killer you're interested in?