Last survivor in horror/slasher films forced to confront the killer — psychologically grounded, often coded as virtuous or asexual. Genre convention since '80s.
You need a character who forms the last line of defense against your killer — someone who isn't simply mowed down like the others, but actively fights back. That's the Final Girl. She's not the first to die, not the second, not even the third. She's the one left standing on the set of horror when everyone else has already landed their scenes in the edit. From a directorial standpoint, this works so powerfully because you build a psychological expectation: the audience knows that one will survive, but not who — until the film's logic reveals it.
The convention established itself through the slasher wave of the 1980s, where you quickly realized that it works more dramatically if the final confrontation between the survivor and the killer carries the entire final sequence. Laurie Strode in Halloween is the textbook example — not the most sexually active, not the most rebellious, rather the more introverted character. This is no coincidence. As a director, you consciously choose this character because she is morally read as worthy of survival. She has behaved chastely — in the classic slasher pattern — while others experiment or cross boundaries.
In practice during shooting, this means your Final Girl needs a different quality in the eyes of the camera than the other victims. She is more focused in the staging, her scenes are framed tighter, her gazes held longer. The edit will later reinforce this difference — her reactions are given more time to breathe. You shoot her escape scenes with more spatial clarity, while the killer's attacks on other characters are edited more chaotically, faster.
Important: This convention is not set in stone and has long since evolved. Modern horror films consciously break with it — some let the Final Girl fall, others elevate the asexual quality and write more complex survivors. But if you want to use the rule, understand its function: it creates narrative and moral stakes. The audience invests in this one character because the film language tells them she is different from the others. This is pure directorial work — not in the performance, but in the framing and timing.