#perceverse

humanity in 40k is known for their affinity in genetic engineering, and never particularly shied away from experimenting on their own people.

Baal's moons were prosperous civilizations during the DAOT, and for the Age of Strife for a chunk of time. Significant chunk of this populance, especially its menials and its security corps would have their genetic strands edited to enhance their strengths, their durabilities, their fast healing.

War breaks out, destroying nearly the complete ecosystem on both moons, leaving only a handful of survivors on each world fending for themselves in the irradiated carcass of their fallen civilization, and over time, their genomes, which have been relatively stable for as long as the civilization actually stood... begun to unravel under the ceaseless radiation.

The sad part is, the effects were mostly physical. The onset of madness began to manifest first and foremost when the less affected human populance began pushing them out of their tribes, and were left to fend for themselves in the wilderness where their minds would further unravel.