Yersinia Derbynis, more commonly known as Eyam's Cleft, is a disease that the PC will receive in the beginning of the game. It was named after the town of Eyam, a village which isolated itself off from the rest of the world to avoid spreading the plague.

The scientific name of the disease indicates that it is closely related to the bacterium that caused the Black Death and other plague outbreaks, Yersinia pestis.


The town of Eyam was a source of inspiration for Robert Sherman, author of The Black Crown Project. On his blog he writes:

My boundary may be a little more grand than Eyam’s, but Eyam’s was here first, and the Coolstone was the foundation that sited every other angle in the Institute. The Boundary Stone is more than a marker, it is an anchor, stopping the Institute from sliding into the ocean, and as we walked along the tracks past houses full of electricity and plastic rinse aids and fruits from very far away, I thought about the Coolstone as an anchor for the village of Eyam.