Replicant
As David Peoples was re-writing the screenplay, he consulted his daughter, who was involved in microbiology and biochemistry, who suggested the term "replicating", the biological process of a cell making a copy of itself.
Tyrell was killed during the events of the first film in November 2019, and the secret of producing replicants capable of procreation died with him.
The pulse destroyed most records about replicants, making it difficult for humans to track them down on Earth, but the attack led to mass purges and complete shutdown of Nexus-8 production (though many existing units were able to go into hiding in the chaos).
The demonstrated effectiveness of Nexus-9 programming, combined with the solving of a global food crisis, allowed for a successful push for the ban on replicant production to be lifted.
Special police units are tasked with tracking down any that might go rogue, as well as any remaining Nexus-8s still in hiding (Nexus-7 was never mass-produced, and all the Nexus-6 models died of old age decades before).
A primary element of the Blade Runner film is the ambiguity over whether the protagonist, Deckard, is a human or a replicant.
"[4] Author Will Brooker has written that the unicorn dream may not be unique to Deckard and that it may be a personal touch added to some or all of the Nexus-6 replicants' brains.
[5] Paul Sammon, author of Future Noir: The Making of Blade Runner, has suggested in interviews that Deckard may be a Nexus-7 model, which possesses no superhuman strength or intelligence but does have neurological features that complete the illusion of humanity.
The film's Supervising Editor Terry Rawlings remembers that Scott "purposefully put Harrison in the background of the shot, and slightly out of focus, so that you'd only notice his eyes were glowing if you were paying attention... Ridley himself may have definitely felt that Deckard is a replicant, but still, by the end of the picture, he intended to leave it up to the viewer.
"[8] The sequel, Blade Runner 2049, revisited the question while leaving the answer deliberately ambiguous.
Niander Wallace, CEO of the company that produced replicants, captures Deckard and muses that his falling in love with Rachael seemed too perfect, suggesting that Deckard was designed to fall in love with Rachael as part of Tyrell's experiment to develop replicants that can procreate, but with Tyrell dead and the records destroyed, he will never know.
