March of Blood
Long ago the tribes of the Devastated Wastes made deals with demons and forces of the Elemantal Chaos in exchange for strength and power. This strength and power, unfortunately for them, did not come with the intelligence to be used properly and while they were made a powerful force, constant animosity and infighting has prevented them from becoming the world power they had hoped to become. As part of a pact with the demon prince Demogorgon, once a year a large sacrifice of sentient beings must be made in his honor, afterwards a demon will emerge and band together the tribes, leading them south on a warpath of destruction. Synp was created by the civilized races as a buffer from the tribes of the Devastated Wastes, taking on the March of Blood every year. Recently the March of Blood has become stronger than usual, and Synp has been taking much heavier losses fending it off.