'Beastmen. The savage swords of chaos, are unleashed! ' From Axioms Compendium 1-8 From Autarch For Adventurer, Conqueror, King rpg

The hordes of chaos are unleashed in Adventurer, Conqueror, Kings rpg as the warriors of evil become an infection on the face of a campaign! 

The Adventurer, Conqueror, King rpg has a number of rpg options thanks to the Axioms Compendium & one that comes to mind is unleashing  the hordes of Chaos! 'Beastmen. The savage swords of chaos, are unleashed' is a great mini sourcebook for ACK's.  Beastmen are the barbarian forces & army  to the ACK's late Roman empire. As the beast men move into an area they go from being simple dungeon dwelling monsters to full on forces of darkness. And these hordes literally lower the property value of any place they move. 

Swamp Troll by Severdhead on Deviant Art 

The humanoids become organized under chieftains & leaders changing the tribal dynamics. Areas can fall under the evil influence of these monsters. The most experienced warriors become the leaders of the new face of the tribe of monsters. No where is this more evident then in AX1  'The Sinister Stone of Sakkara' which sets up the hordes as one of the game's main optional enemy. 

Though they can remain trading partners & the like in ACK's these forces are pure evil. They entrench the forces of darkness within a campaign setting. 'Beastmen. The savage swords of chaos, are unleashed' sets up not only the range of these hordes but echoes the economic realities of living with scourge of the humanoids within a campaign. Why!? Because the places where the beast men settle becomes the perfect breeding ground for greater evils to come. This is a pattern that we see over & over within ACK's itself. And this 'Russian doll' nesting of the forces of chaos is evident by the AX2 Secrets of the Nethercity as well. Make no mistake the forces of chaos are the shock troops of the greater fold & the leaders. Evil begets evil. 

And the forces of chaos have fallen way down the long ladder of civilization because while they can use the tools of mankind to reach the stars. These horrors can & do adapt the tools of mankind ie space craft. They can't create new innovations that mankind can or at least this is how it is within my own campaigns.