Rather than being a conventional mod, these files will essentially serve as a proof-of-concept template to demonstrate the potential of a certain type of creature one can create. Essentially, through the clever use of descriptors and custom body parts, one can create societies of intelligent savage species armed with various weapons and have them spawn within the game, adding a new level of difficulty to the world along with making it seem more alive (at least until toady adds actual savages and nomads hahaha). In addition, those making specific scenario or setting mods can reverse-engineer the template I have provided into a new variation that suits your needs. You could create bands of cultists armed with daggers and dead-raising priests, or club-wielding and stone throwing giants in the plains. Here's an overview of what I have created, to serve as an example of the potential of this mechanic.
http://dffd.bay12games.com/file.php?id=14214The example species is the Wildman, a primitive variation of human that wears fur pelts and uses face paint, which will both show up in its generated descriptions. Hunters will carry copper spears, Slingers carry slings that can throw lead slingstones, berserkers carry a pair of axes and have increased skill in their use, champions wear iron armor and carry a sword, and shamans carry bronze staffs that can summon fireballs. All of these types exist within the same species but at different ratios. For example, 60 out of 100 wildmen will be hunters, and 1 in 100 will be shamans. In addition, they have a high population (as many as 100) but only a 2 percent chance to spawn. But when they do, they can appear in massive numbers. They will appear in any temperate savage forest and could easily be a major early game threat comparable to werebeasts due to their metal weapons. Effectively, its like being subjected to a small invasion. And last but not least, these creatures should be able to be captured in cages and tamed (enslaved) by the player and in world gen, meaning not only will invaders have the chance to show up with wildman thralls, but the player ought to be able to use them as well. Because they have the [CAN_LEARN] and [SLOW_LEARNER] tags, they can help haul things and learn to fight better, but cannot be butchered for meat (you can change this by removing these tags from the creature). In addition, I have removed the [EQUIPS] tag because it would interfere with their "natural" armor and clothing.
In summary, this technique can be used to create mid to high level bands of roving enemies that can simulate the feeling of nomadic clans, bandit tribes, or marauding hordes. It is somewhat janky from a roleplay perspective as you cannot actually interact with or play as creatures of this nature, only kill or enslave them. However, from a pure gameplay perspective I feel it can create a respectable threat even to late game fortresses depending on the creatures created.
Anyone may use the wildmen themselves in their own mods, and I encourage anyone who takes a look at this technique to devise their own unique enemies. I have tried to create a great many subtypes so that the way they are created can be understood (knight, wizard, footsoldier, veteran, archer) and expanded upon. Hopefully someone finds it to be of use.