As they naturally befoul anywhere they linger, Skaven corruption causes settled provinces to become less hospitable over time, even for Skaven.
Skaven corruption is spread wherever the Skaven settle. From their underworld cities they fight tooth and claw against the other races – and each other – to further their personal standing within the Skaven heirarchy and to serve their diabolical god, the Horned Rat.
The verminous Skaven are a race of malevolent and self-serving ratmen.