Source: Cheliax, The Infernal Empire, pg(s). 47
Having long been interested in Shub-Niggurath's terrible power and fertility, Vediss Halurexis discovered the existence of the Gibbering Blot in 4713 AR when conducting illegal research in Egorian about her cult. He believed that according to the prophecies he found, when the Gibbering Blot is freed, Shub-Niggurath will return to Golarion, destroy it, then make him powerful, and allow him to rule over its ruins in her name. For a few months, he preached to Egorian's most despised and downtrodden, promising them a world where they would rise above those who once oppressed them. Halurexis then moved to the Whisperwood, near the Pillar of Palamia, with a few dozen converts in tow, and continues to research how to free the Gibbering Blot.
After years, Halurexis successfully opened a small rift into the shoggoth's prison. This fracture is enough to leak an aura of madness into the surrounding area, twisting the forest paths and animals alike, and spewing forth particularly grotesque aberrations (even by their standards). As they discourage most creatures from approaching the pillar, Halurexis and his minions have started to sneak into nearby villages to abduct people wandering the streets at night whom they then subject to profane rites.