After accidentally being left with the inmates alone for some time, Amanda was found to have been sexually assaulted over 100 times and found pregnant. This gives Freddy the title "son of 100 maniacs" and his DNA combined with an abusive home life made him into the human monster that he was when alive.
In the original movies (those covering from Wes Craven's A Nightmare on Elm Street to Freddy's Dead: The Final Nightmare), it was explained that while he burned, he was approached by Dream Demons who made him an offer: they would give him immortality in exchange for being their agent, allowing him to continue his ...