Koromite is a dense purple stone that was created by the Dwarves as a way to control the magic energy around them and manipulate it into physical form. It has a dastardly effect on the environment around the user.
During the War of Depravity the Dwarves needed something to fight effectively against the Elves, to do this they created koromite. It lets the user control the magic energy that they were otherwise unable to use, and manipulate it. This gave them great power over the Elves because they could match their magical strength and overpower them using brute force coupled with numbers.
The Humans just as the dwarves had a need for such a useful resource. Without the ability to control their magic, and with no way of knowing their individual magic elements koromite was invaluable. Many of the kings across Delsden bought bulk supplies of it for massive sums of money (Usually more than 500,000 [[Star|Stars).