The manifestation of the greater presence of The Deeping and its effects have had a massive detrimental impact. It is believed that its sheltering of species and creatures that would normally have been hunted to extinction or killed is directly responsible for the lack of technological growth and several massive setbacks of the development of the Steel Realms.
If nothing is indicated, assume Common Knowledge.
Most Recent Stirrings
The earliest corruption which is thought to be the origins of The Deeping in the realms is the Valley of Sighs. Because several minor and demigods died there, as well as the wounding of the demiurge of the world spirit of Helca, it was less a single powerful god and more the lingering essence of several lesser divinities. The prolonged orgy of terror and violence were the catalyst.