Replicants are androids, or robots in human form. Created by Eldon Tyrell and the Tyrell Corporation, they can do many different kinds of work. They're especially well-suited for hard labor or jobs that are too hazardous for humans to do. Advertisements for moving to the off-world colonies promote the opportunity to own a replicant as an incentive. There are also other synthetic life forms available to those who can afford them, including snakes, fish and the owl that Deckard sees when he visits the Tyrell Corporation. The replicant, however, is the epitome of robotic life.
Genetic engineers design replicants and other robotic life forms from a combination of organic and synthetic materials. Though they are designed and built as machines, to some extent they grow organically.
Tyrell's Nexus series replicants, brought to market after the turn of the 21st century, blur the line between humanity and robots. The most recent model, the Nexus 6, is stronger and smarter than the engineers who created them. Nexus 6 androids are almost indistinguishable from humans, except for one major difference -- they were designed to have no emotions. Because of their sophistication, however, Tyrell's engineers expected replicants to develop emotions on their own. The Nexus 6 developers built in a four-year life span to counteract the androids' ability to adapt.
However, this plan was only marginally successful. After a bloody uprising off-world, replicants are illegal on Earth -- but that doesn't stop them from trying to reach the planet. Unfortunately, the six that jumped the shuttle for Earth are all trained for combat, which makes them particularly dangerous. One of them dies in an electrical field as the group attempted to break in to the Tyrell Corporation. We know the identities of only four more:
- Roy Batty, a combat model for the colonization defense program
- Pris, a standard pleasure model for military use
- Zhora, trained for political homicide
- Leon, a combat model
What they want is simple: a longer life -- more time than the four years they've been given. As with most self-aware, living beings, they don't want to die.
Despite the prohibition on replicants, these six are not the only replicants on Earth. Rachel, who works at the Tyrell Corporation, is an experimental model even more sophisticated than the Nexus 6. It has a set of implanted memories, based on those of Tyrell's niece. Fake memories, Tyrell believes, make it easier for the androids, who are less experienced emotionally, to cope with their emotions. Having implanted memories will also make replicants easier for humans to control.
With the hazards replicants pose to humankind, why would the Tyrell Corporation continue to make them? One reason is that they still sell well among people off-world. The company also wants to improve upon its work, trying to achieve its motto: "More human than human."
Escaped replicants created the need for a whole new type of law enforcement. Next, we'll learn more about blade runners and what makes them tick.