Early in the 21st Century, THE TYRELL
CORPORATION advanced Robot evolution
into the NEXUS phase - a being virtually
identical to a human - know as a Replicant.
The NEXUS-6 Replicants were superior
in strength and agility, and at least equal
in intelligence, to the genetic engineers
who created them.
Replicans were used Off-world as
slave labor, in the hazardous exploration and
colonization of the planets.
After a bloody mutiny by a NEXUS-6
combat team in an Off-world colony,
Replicants were declared illegal
on earth - under penalty of death.
Special police squads - BLADE RUNNER
UNITS - had orders to shoot to kill, upon
detection, any trespassing Replicant.
This was not called execution.
It was called retirement.