Peregrim's World was an industrial Agri-world of the Imperium located in the Affluix Sector dedicated to producing massive amounts of grox-meat for the sector. It was infested by a gene-sect of the Innerwyrm Genestealer Cult and its exports of meat used to expand the infection across the local stellar region.
After the formation of the Great Rift, the Cult of the Innerwyrm spread far and wide across the Affluix Sector by using the grox-meat export network of Peregrim's World. The steroid-enhanced beasts grown by Ethod Peregrim's famous meat dynasty reached truly massive sizes, altered by the dictates of the industry's selective breeding to have vast torsos and abdomens -- large enough to contain Purestrain Genestealers sewn into their guts by Innerwyrm abattoir workers.
By sending the massive grox carcasses to a dozen different worlds in the famously paranoid Fort Adere star system, the Innerwyrm agents bypass the complex bio-scanner protocols that would otherwise have picked up on the biological tissue of the Genestealers smuggled within the meat. A new ecosystem is born on each of the infested planets, though it is not just grox meat that forms its sustenance.
- Codex: Genestealer Cults (8th Edition), pg. 39