Fellstone

Fellstone is a strange substance hailing from The Outside. It does not occur naturally, its poperties are a closely guarded secret and many groups across the realms immediately destroy the substance if they encounter it.

Description:

Fellstone is a rock-like substance that has a color between grey and purple. Fellstone feels oily to the touch and is brittle, splintering more easily than most rocks.

Forbidden: Fellstone is forbidden by the very highest authority in the brass realms: The Three kings. Thus it is banned by any religions that align themselves to any of the three kings which many of them are.
Oficially, fellstone is described as a dangerous poison that is not especially effective but very cruel and painful. For this reason its trade is prohibited and persecuted more harshly than even other poisons.

Creation:

Fellstone is brought into the brass realms by outsiders. It is not a natural substance and is imposible to synthesize.

Uses:

Mutator: Fellstone is highly hazardous to life. If Fellstone dust is breathed in it causes cancers in the lungs, and if eaten causes stomach cancer. If not lethal, exposure to Fellstone can cause mutations and Star-touch. Consuming Fellstone and surviving the experience also breaks the Taboo.

Rulebreaker: Fellstone is a material from beyond the brass realms. It is thus not fully bound by the rules of the brass realms. Thus it is possible to use Fellstone to break the laws of physics, magic and spirits to accomplish otherwise impossible things. Examples include breaking unbreakable barriers, killing immortals and time travel. However it can be very inconsistent in its rule-breaking and requires long dedicated study to utilize.
The breaking of the realm's rules is actively harmful to the universe and the brass realms themselves.