Mountain Steel is a scarce kind of metal that is incredibly hard to destruct, only to be found in Falder. It is actually not an element alone but a mixture of many minerals, making it impossible to be produced artificially or with alchemy.

Since its discovery, it has been targeted, seeked and mined by industrialized kingdoms, and been a reason to fight over. Very small amount of it can be found on southern Shady Mountains, Wicked Mountains and Three Horns Mountains, and massive amounts of it can be found on middle and northern Shady Mountains, where the home of Kavkassians is at. Kingdom of Steichnia and Kingdom of Russhland has been fighting over it against the Kavkassians for about a hundred years. Kavkassians refuses to give neither their homeland nor Mountain Steel to anyone, they believe that it is a gift which is granted by their smith god Tlepsh for them alone. And due to the rarity and value of the Mountain Steel, the two kingdoms have been committing all kinds of barbarism upon them.