Inhabiting Orsinium, the Gretchin are the progenitors of modern-day Orks, descendants of the greenskins that long ago were denied the right to consume Meat-shrooms, the food which first gave Orks the strength and size they are known for.
Throughout Orkish history, Gretchin have been used as slaves, footstools, or cannon fodder by their larger cousins, and are little more than a client race. Despite this, a few Gretchin have managed to rise above their lowly stations, such as Grot-boss Shub, who served as the right hand and strategic mind to Warbosss Grimskull during the Mythic Dawn Crisis.
Old records tell that in the ancient past, before the rise of the Elven empires, the primitive Rieklings of the isles of Sol-stam were engaged in a two-sided war amongst themselves. They fought for unknown reasons, likely because of land disputes or perhaps some disagreement in their primitive religion. Regardless, after many long and bloody years, the more warlike Riekling tribe was defeated. These Rieklings abandoned the Sol-stam Isles, and fled by wood rafts to the continent of Orsinium. Here, they discovered a mysterious fungus known in their tongue as "Grez'thuz", later known better as Meat-shrooms, and it became their primary diet on Orsinium. It was around this time they began to refer to themselves as Gretchin.
This fungus eventually turned the Gretchin skin green, and their populations skyrocketed. Over time, this fungus revealed parasitic qualities, which were unnoticed by the Gretchin, since they were so unintelligent. The fungus became symbiotic to their very beings, and evolved them rather quickly, altering their very DNA to suit the fungus' own will. After barely a few hundred years, Gretchin lost their fertilities and whatever females existed seemed to have died out. Instead of going extinct however, the Gretchin still continued to grow in number, quicker than before. It turned out that the Gretchin were reproducing through spores which came from their fusion with the Meat-shroom fungus.
Several generations later, greenskin runts began to spawn with different appearances from the Gretchin. These ones had sunken noses, large jaws, massive muscles, and were far more violent. These were the first Orks, which grew far larger and stronger than any Gretchin. Through superior strength and brutality, the Orks became the leaders of society, and amplified the Greenskin's prevalent lust for war, or, as the Orks called it, WAAAGH! The Orks lorded over the weaker Greenskins with force, and the Gretchin could not hope to question their Ork cousins.
The Orks and Gretchin collaborated together to form functioning, if primitive, hierarchies with the Orks on top, and the "Grots" on the bottom. The Gretchin had not the will nor ambition to dislike their position or challenge their Ork overlords, for fear kept them in line, and the hope to win favor with the large Greenskins.
Gretchin nowadays are sent in large packs to take out enemies, or to serve as distractions while larger orks move into position.
However, the most notable and esteemed Gretchin of all time was the War-Marshall Shub, the right hand of Warboss Grimskull during the events of the Mythic Dawn Crisis. He is one of the extremely few Gretchin to ever gain respect from the orks, and the only one to gain the respect of a Warboss, and the only one to ever serve as his right hand War-Marshall.