The New Gods rose against the Forgotten Gods in a violent battle at the end of the Earliest Age, tossed them from the high Hallows Above, and entrapped them in the Mortal Realm and the Circles Below. To trap the First Doom in particular, they split part of his being into nine pieces and gave the shards to nine mortals to hide. They also left blighted earth around Godfell Mountain to keep mortals away from the ancient god's prison.
Per the prophecy, the New Gods will fall from the Hallows Above and Kudamat will slay them with his stone sickle, that their blood will flood the Mortal Realm.
In the Drylands, some worship the New Gods and believe essentia is a profanity — a few enough to commit crimes to close the mines in their name.
Source · Drylands History