Story structure
Femme fatale
The 'fatal woman' stock character: a mysterious, beautiful, seductive woman whose charms ensnare her lovers, often into compromising, deadly traps.
A femme fatale, "sometimes called a maneater, Mata Hari, or vamp," is "a stock character: a mysterious, beautiful, and seductive woman whose charms ensnare her lovers, often leading them into compromising, deadly traps." She is "an archetype of literature and art," typically "villainous, or at least morally ambiguous," whose power over her victims the earliest stories saw as "verging on supernatural." Her ancestry runs from Circe and Medea through Cleopatra and Morgan le Fay, the Romantics gave her Keats's "La Belle Dame sans Merci," and the hardboiled crime stories of the 1930s pulps made her standard issue: Phyllis Dietrichson in Double Indemnity (1944) "manipulates a man into killing her husband for financial gain."
Her craft value is compression: one figure carries desire, danger and deception at once, which is why noir keeps re-casting her as the corrupt system's most attractive door. The risks run the other way: kept as a pure device she flattens, and promoted to viewpoint character she needs a want of her own beyond the trap. A love triangle with her at the apex is the classic staging, and the story usually lives or dies on whether the reader's sympathy survives the reveal.