Peoples: The Servants

These are the battle-fodder of the demonic army and are by far the most common type of demon. Despite this they appear the least often of all the demon species and lack any sort of influence in the Demon Empire. They are the workers, fighters, and mobs wielded by the kings of demonkind.
Physically, servants look like a scrawny man with no hair, bright red skin, pointed ears, tiny horns of ivory, sharp claws, and a rat tail. They are slightly shorter than men but some can grow to be much bulkier. They are no very intelligent albeit smart enough to take orders. Their vocabulary is limited and their voices are soft and hissing. Baby servants are born from pools of servant saliva and refuse. Their demon masters have perfected these "spawning pools" and built lake sized pools that churn out hundreds of the creatures every week. This, coupled with the fact that servants do not need to eat, ensures that their population is in the tens of millions, even in lean and hungry places within the Demon Empire. Unsurprisingly, their wicked masters take to dining on their flesh if food is unavailable.
They behave like rats (causing some people to call them rat-people). They breed in massive numbers and live in shadowy areas, ruins, or other places that people don't bother to chase them out of. If a demon warlord wants an army, all he needs to do is look in dark places and he'll probably find a nest of servants. Servants are a disorganized society, having no leaders of their own. Instead, they follow whatever powerful destroyer catches their attention. Their loyalty to these leaders is unshakable. They are smart enough to learn some bits and pieces of the demonic honour code, thus earning them the trust of the empire.
Unless given weapons, servants will fight with their claws or whatever they can pick up. Servants have gone into battle waving sharp sticks, rocks, bones, and furniture. When they are armed they are given cheap, simple weapons that are capable of being mass-produced. Then they are thrown into battle, showering on the enemy in wave after relentless wave of scuttling bodies. In book 3, a typical servant warrior carries a buckler, a short axe, and wears a helmet made of a metal plate beaten into a rough bowl shape with studded leather armor.
Poor fighters, it is said that one soldier can take down five armed servants all on his own. A squad of men working together can kill a swarm of them. But the bastards keep coming. In the story, the servants are an enemy for the heroes to kill in large numbers, without resorting to the "Stormtrooper Effect" thus the story is more believable. If I want to bring on the pain, the socrighters or destoryers make an appearance, but if it's going to be a heroic RPG moment then the servants will swarm forward.
Here's a quote about them:

"We don't really think of them as members of the empire. They're more of a tool to be used, and expended, for greater gains. We regard them with as much dignity as a musketeer gives his ammunition. Well, actually no. A musketeer has only so many shots."