Changes
The Change. When the last of the great plagues effectively ended human civilisation, it also left its genetic marker in every survivor. In general terms, about half the population born since the change [it varies from area to area] manifests some physical change in form from baseline Homo Sapiens Sapiens. Very few people from before [people who survived the plague] have physical manifestations and they are mostly minor.
Game mechanics
Age groups born since the change use the Post Ruin table below. Older characters use the pre ruin one - unless they were undergoing puberty while contracting the virus, in which case they roll on post ruin results.
Every PC is changed. Roll once on the tables below - twice if born after the event.
Change results [on D20]. Minor change: No visible sign and would need specialist equipment to determine. [Pre ruin: 1-10, Post Ruin 1]
Coloration/Melanin change: This varies from purely random blotching to elaborate patterning to a skin tone change to the truly odd. [Pre 11-14, Post 2-3] Skeletal modification: Ranges from extra or fewer fingers and toes through to complete skeletal change [gigantism, dwarfism], including different physiological typing. Increased or decreased blood/white ellproduction, weaker or more flexible, etc. [Pre 15 Post 4-5]
