Skytanium

Skytanium is the hardest substance to exist in the world of Enarch and is very highly valued. The limited quantity of it in the mainland caused it to be nicknamed royal gold during the first and second tales. During the third tale however, the explorer Tendrin Y'finch discovered the metal in the gate mountains of the continent of Yenera. The discovery eventually became one of the key causes of the Plutonian victory in the Fourth Great War. Only in the ninth tale was a harder substance, lunite,  found on the surface of Enarch's outer moon.