Unknown; Frigid due to lack of sunlight
Medusa is the Chapter homeworld of the Iron Hands Chapter of Space Marines. The Feral World of Medusa is a harsh realm of perpetual gloom, situated precariously close to the Eye of Terror in the Segmentum Obscurus. The sun almost never breaks through the dark and polluted sky, as it constantly churns over a land of frozen mountain ranges, interspersed with volcanoes and boiling hot geysers. The landscape is under constant flux, the shifting of tectonic plates forming new mountains and seas, and destroying them as quickly as they are created.
The skies of Medusa are always dark and choked by volcanic ash, and its lands are blasted and barren. Massive mountain chains rise high above the land and the peaks of the countless volcanoes are so high that they pierce the black clouds and illuminate them from within as if they were gateways to the infernal. The poles are freezing and savage and the Land of Shadows is a silent region of this barren world that is strewn with alien ruins millions of years old that some Imperial savants believe may belong to the ancient Necrontyr civilisation.
Karaashi, the Ice Pinnacle that the newborn Primarch Ferrus Manus' gestation capsule crashed into when he first fell to Medusa, can still be seen today, though it is said to be half the size it once was. A great gaping hole at its peak that spews ash and steam into the atmosphere is evidence of where the shining light of Ferrus Manus crashed millennia ago. Still it rumbles with the constant geological anger of Medusa -- a constant reminder to the planet's people of the need for vigilance. The clans of Medusa prepare for that day when the Ice Pinnacle ceases to rumble Medusa's unease. For that day, it is foretold, will mark the second coming of the great Primarch, and with his return, even the volcanoes of Medusa will at last be content.
The people of Medusa are truly a product of their difficult environment. Harsh and unforgiving in nature, Medusans are a fierce and hardy people who cannot afford to brook weakness of any kind in their ranks. Those who are too weak or sick to survive without aid voluntarily surrender themselves to die amidst their world's elements so that their lives will not drain the existing resources and put their friends and family at risk. The people are organised into nomadic clans and while in ancient times they trudged across the ever-shifting landscape on foot or astride the backs of sturdy beasts of burden, they now travel in vast processions of ramshackle tracked vehicles each as large as a fortress, the acrid stink of a thousand new engines adding to the sulfurous pollution already present in the atmosphere. It is from these hardy and stoic people that the Iron Hands Space Marines exclusively recruit their Neophytes, for the world, its people and the Chapter are one and inseperable.
The Primarch Ferrus Manus saw that weakness could kill the people around him, and came to believe that infirmity of any kind was a plague. He believed that it was better for the weak links of humanity to be destroyed than to have them pose a threat, an unnecessary frailty that would pose a burden to the rest. On Medusa, weak children were routinely exposed to the elements so as not to place an unnecessary encumbrance on the rest of a clan's community. So too, when the time came that an adult was incapable of providing for the community, that person left their clan. Those who accepted the Emperor's Divine teachings were embraced. Those who did not were cut down without pity. The ruthlessness of the Legion and its Primarch terrified those who stood in the way of their relentless approach, and many worlds turned to the Emperor out of the overwhelming fear of retribution that these callous warriors were becoming renowned for.
- Codex:Space Marines (5th Edition)
- Index Astartes IV, pp. 47-48
- Deathwatch: First Founding, pp. 7-8