Gretchin or Grotz are basically a smaller subspecies of Orks, who are more cowardly than normal Orks and are usually used as living shields, to clear mine fields, are stepped on to get through difficult terrain, and sometimes even as emergency rations.
Gretchins are quite low in the strict hierarchy of Ork society because of their small size (the lowest Orkoids being the Snotlings) and are often used for the dirtiest jobs like scavenging and being used as the football when the bigger Orks get bored.
Gretchin mobs more than make up for their unmistakable lack of quality with sheer numbers. The natural gutlessness and complete incompetence of the Gretchin race does not make them accomplished in the arts of war. Your average Grot would rather hide or bury his head in the sand than actually partake in a full fledged battle.
Ork Gretchin consists of 11 unpainted miniatures, assembly required