Goblin armies are made up of disparate clans from across Pannithor, typically brought together by the delusions of an individual goblin determined to rise to the lofty position of the goblin king. Goaded and pushed into battle by their superiors, what goblins (severely) lack in training and tactics, they make up for in sheer strength of numbers.
There is no one goblin kingdom. Instead, large clans are scattered across the land, each with their own self-elected (and often tyrannical) leader. It is not uncommon for these miniature megalomaniacs to declare themselves king – and there can often be multiple goblin ‘kings’ ruling at any one time. Typically the kings will spend the majority of their short-lived reign fighting other goblin kings or hiding away from would-be attackers. If any goblin king ever managed to survive the petty squabbling and back stabbing to unite the clans in a common goal, it would be a dark day indeed for the other races.
– lore snippet from 3rd Ed. Rulebook