However, this is the power of the royal families of various countries, and no other noble can meddle with it, for whoever does so is courting death.
There are three kinds of mines that are even more profitable than gold and silver mines, and they are not exclusive to the royal family. They are the three secret metals: Secret Black Gold, Secret White Gold, and Secret Dragon Gold.
Each of these three secret metals is a priceless treasure, worth several times more than an equal weight of gold. Without exception, they are all related to martial strength.
Secret Black Gold is an extremely hard and heavy metal. Strong warriors use it to forge swords, while dragon archers use it to make arrowheads. Arrows forged from Secret Black Gold are utterly indestructible.
The last time Suo Lun spent a large sum of gold coins in the southern border, he only bought black gold-plated arrows, and they were already indestructible.
