Warlords of Erehwon is a fantasy based game designed for 28mm tabletop warfare. The gameplay is built around the D10 system developed for the science-fiction game Beyond the Gates of Antares and also using the praised order dice mechanic first used in the Bolt Action WW2 rules.
The undead horde is primarily made up of corpse-soldiers that we call skeletons but the list can easily represent a variety of interpretations of undead warriors in various states of decay.
Orc leaders are if anything bigger and even more brutal than their troops. Chieftains can be armed with huge swords and are prone to making ferocious charges, but otherwise carry the usual weaponry and limited armour.
Skeleton troopers can be insubstantial spectral creatures if we wish our forces to represent the spirits or essences of long-dead warriors rather than their material remnants
Orc warriors are big brutes that favour crude weapons that we call swords for want of a better word but might equally well be described as cleavers, butchers knives, machetes and hedge hooks