Medusa

Medusa is the homeworld of the Iron Hands Space Marine Chapter. It is situated dangerously close to the Eye of Terror, and as such is located within the Segmentum Obscurus.

It is a bleak world locked in perpetual gloom. The sun almost never breaks through the dark, polluted sky and the planet is mostly a range of ice capped mountains interspersed with volcanoes and boiling hot geysers. The planet is unstable and the tectonics plates are constantly shifting, creating and destroying oceans and mountains.