In the Lith-Crillion Era, the Gud-Mortoth was a Orc tribe that wandered far and wide. They travelled to the four corners of Brucrumus, several times nearly wiped out. In the Horgon Era, they were living in the Mynzuth hills overlooking the Mortoth plain. They were one of a dozen orc tribes in the area. The others were breakaways from Gud-Mortoth. Each of these breakaways fell sway to Gruumsh's words, a storied general, that visited their encampments. He told them that demon agents were using the Gud-Mortoth to divide his people.
In 252 HE, the Gud-Mortoth were driven from their lands by Gruumsh's orc alliance. This was carried out in crusader fashion, with the alliance purging the conquered as well their own of any considered to be doing the work of the demons. Gud-Mortoth's shamans gave orders for a fighting retreat towards the Kamoni jungle. It was a decision initially laughed at, even drawing fear. Most of the orc warriors, with traditions dating back to the demon war, inspired by Gruumsh's war journals, would rather die in battle than eke out an existence in the Kamoni. Infilitrated by Demogorgon cultists, their shaman leaders made the final decision. When the shamans spoke in unison, guided by Demogorgon's own words, they were told they brought shame on Gruumsh, they needed to be hardened by the environs of a jungle, and prove their worthiness to Gruumsh. Most of the listeners were enraptured, obediently following their shamans into the jungle. Over the next eight years, they wandered, suffering sickness and battle. After being reduced to 20% of their original number, and the execution of several stubborn shamans, execution of all their shamans, the Gud-Mortoth stopped wandering. In 260 HE, they began building the Tarkrath citadel.
In 265 HG, assassins in the service of Gruumush cleansed the tribe for the last time, ridding it of demon influences. This led to the elimination of 21 Gud-Mortoth shamans. For Demogorgon, the demon lord who had been behind the tribe's misfortunes, this resulted in a noticeable loss of divine power.