Who is the main antagonist of the "A Nightmare on Elm Street" film series?

Freddy Krueger is a fictional character and the main antagonist of the "A Nightmare on Elm Street" film series. He first appeared in Wes Craven's "A Nightmare on Elm Street" (1984) as the spirit of a serial killer who uses a gloved hand with razors to kill his victims in their dreams, causing their deaths in the real world as well. In the dream world, he is a powerful force and almost completely invulnerable. However, whenever Freddy is pulled into the real world, he has normal human vulnerabilities and can be destroyed.

The original film introduced his backstory as "The Springwood Slasher", a serial killer of children who had been burned to death by his victims’ parents after evading prison. This alias would be used in other films and media throughout the franchise, such as Freddy vs. Jason and the "Nightmares on Elm Street" comics.