The subtle poison known as “Rustcaller Toxin” was first attributed to the Woebringers, a murderous band of religious zealots prominent during the religious wars of the previous century. Distilled from the sap of several desert plants, it is actually easy to manufacture, but because the needed plants serve no other purpose, mere possession of these ingredients is considered sufficient justification for execution among the desert tribes that populate the plants' growing range.
Transparent and vaguely oily when first applied, Rustcaller Toxin is actually quite harmless until it has had time to react with a metallic surface. In fact, Rustcaller requires several days to reach its true, lethal potential. Reacting with iron alloys, nickel, or manganese, once wiped onto such metal, the poison gradually changes to a rusty red-brown often mistaken for rust or corrosion.
In this state, the toxin is a slow, but deadly contact poison. The first sign that one has been poisoned is a blackish stain on the involved body part. The stain soon begins to burn and itch: victims who swiftly amputate affected fingers or hands have often been saved at this stage. Over the next few days, the poison destroys the victim’s kidneys: They grow fatigued and confused, suffering agonizing abdominal pain, and urinating blood. Their tissues swell due to wastes retained in the system until they eventually suffer congestive heart failure. If recognized early enough, a vigorous regimen of fruit juices and fluids can flush much of the toxin from the victim’s system, saving their life. Victims may still be disabled for months afterward.
Rustcaller Toxin has seldom been a tool of political assassination, as it is more easily used to spread random terror. Some have used Rustcaller to make otherwise innocuous items into deadly traps. Even a humble door handle or buckle can become lethally toxic.