The Iron Corruption is a supernatural curse, imposed on all inhabitants of Jarneyna, although the curse is mostly affecting Ironlanders.
Origin
Currently the true origin of the Corruption is unknown, but it is speculated that Loki cast the curse before he was imprisoned.
Corruption’s Cycle
Any living thing on Jarneyna is born with a seed of the corruption: The hunger for power and fortune. The corruption itself feeds on this hunger and demands more of its host. The iron acts as a catalyst to live out this hunger. From Iron, weapons are forged to dominate others and exert power. The hunger consumes all thoughts until only it remains, driving the host mad, paranoid and dangerous.
Prolonged exposure to iron will turn the iron in the blood crystaline, that can be visibly seen on wounds on the hosts body. Instead of healing, a skin of pure iron will form over the wound over time.
Upon the hosts death, it will turn the body into a new vein of iron, to be found by another host that turns it into weapons to satiate its hunger. And thus the cycle begins anew.
Cure
There is no direct cure for the corruption, as it is in the nature of the Ironlanders. However there is a way to coexist or delay the effects it has. This needs drastic changes in the way one is living and thus is far rarer. Using silver has a calming and suppressing effect on the corruption, although the resource is much rarer and harder to work with.
Hreinsun
The Nat’las have a ritual called Hreinsun that can flush out the corruption and reverse its lasting effect. Altough effective, most recipients die during the ritual. It is said, that one has to swallow a cup of molten silver, but the full extent of the ritual is unknown.