Goblin

Goblins are the main race inhabiting the land of Ogriss. They were created by Fraziel, seperated from the other races of the world, to assist him with the construction of the Great Machine and possibly other things, as -- despite being presumably tolerant of each other pre-civil war -- each clan boast weapons of war.

General
In comparison to Fraziel, the only human seen in the game, the Goblin Cheiftans were short and their clan brothers were even shorter. Unlike humans, Goblin appearances vary wildly with regards to both skin color and features, due to having been artificially created creatures instead of naturally occurring ones.

Stonekrusher
Stonekrushers are heavyset and strong, built for working in the mines underground, with the exception of the drummer who is quite scrawny in comparison. They are grey colors, and generally tusked, with Grommel being the largest and most impressive of their number as far as normal units go.

Hellfire
The Hellfire clan are probably the smallest in terms of height, and down with plaguespitters in terms of scrawniness. They too are tusked, but are done all over in red to match their namesake. The Hellfire clan typically wears goggles so their eye color is unknown. Grax is somewhat more heavily built than his underlings.

Stormbringer
The Stormbringer clan are a group of blue-skinned goblins, but unlike the Hellfire clan and the Stonekrusher clan, these goblins are quite tall though a few shorter individuals do make up their ranks. Their eyes are red.

Plaguespitter
The Plaguespitters are a group of goblins that boast sickly green colors. Their height is hard to determine as many of them are hunched over for one reason or another (in which case, they'd be the shortest of the five clans). Their eyes are red.

Nighthorde
The Nighthorde clan is arguably the tallest clan, standing equal to or taller than the Stormbringers. They are also quite muscular, though they don't seem as heavy set as the Stonekrushers do. Their skin is dark purple, their hair is black, and their eyes are blue, possibly unique among the Goblin clans.