As we said in the introduction, Blade Runner is the dual-story of Deckard and Roy. Integral to Deckard's journey is Rachael. A replicant working for the Tyrell Corporation (the major company behind the artificials), she is initially oblivious of her true nature, believing herself to be human. As well as potentially drawing parallels to Deckard (more on that later), it shows how belief plays a strong part in identity. The Voight-Kampff test, which by measuring eye-dilation (eyes are a key image throughout the film, serving as a window into the soul) through a series of questions determines whether someone is human or not, normally takes thirty or so questions to tell if someone is a replicant or not, but with the deceived Rachael is takes almost a hundred; in believing she is human, she somehow becomes more human. Part of the deception comes from having memories (from Tyrell's niece) artificially inserted into her mind. She fully believes them, but we (and subsequently her) know they're entirely fabricated. This will prove incredibly important in later arguments, but also brings up the film's question of what it means to be human. With Roy his memories were what made him unique, but for Rachael they're central to what makes her so fake. What's this got to do with the ending? Well, it stems from that Blade Runner is, at least in part, indebted to film noir; the story of a detective coming out of retirement, the trenchcoat and the voice-over are all very noir tropes. By that logic, Rachael should fill the femme fatale role; a woman who ensnares the protagonist with her seductive manner, ultimately to negative effects for the male. While she does lead to Deckard turning his back on the police, it isn't with any malicious intent. Her being so different is what allows not only this subverting of genre conventions, but also the very possibility of a happy ending. And ending which we'll explore next.
