User blog comment:ChishioKunrin/Maidens - Origin of Dust and the Kingdoms?/@comment-25110963-20151216101644

So from what I get from this and how the origins of Dust and Kingdoms relate to the story. Mankind was powerless to Grimm. There was this old man who might have been some kind of wizard, who lived away from the rest of the world in reclusion. Four maidens who were pure of heart in a dark time went to the man for help and eventually recieved great powers after they convinced him. They went out to the world to spread hope to the rest of mankind. They might have gave power to mankind by creating Dust(don't know how) by some process. After conquering the Grimm, they established the four kingdoms,

Enough time would have passed for the Dust (powder, crystals, or residual energy )during the fighting to deposit into the earth and grow like natural minerals.