前作冒頭文全文、レプリはあくまで遺伝子工学で造られたものだよ

Early in the 21st Century, THE TYRELL CORPORATION advanced robot evolution into the NEXUS phase
- a being virtually identical to a human - known 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.
Replicants were used Off-World as slave labor, in the hazardous exploration and colonization of other 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.