Burrowmen are a servant or race of humanity. No independent, settled communities of halflings exist. Instead, halflings live among humans anywhere and everywhere. Usually called "Halflings" by humans, Burrowmen are not slaves per se, since no human actually owns a halfling. However, in order to work, farm, conduct business, or do anything else that matters, a halfling must have a contract. These contracts are held and owned by humans, and are the human's individual property. The newly born halfling is given a contract by the human that holds their mother's contract. These contracts can be bought and sold at will, and humans can indirectly dictate the terms of a halfling's entire life through it. No halfling may be made a citizen of a human nation. Halflings do live among other races, and may be able to live independently, but find their opportunities and status severely limited. On the other hand, a halfling with a contract from a wealthy human merchant or noble house can live a life of power and luxury, rising to high office. A halfling who breaks their contract is subject to punishment, including death.
Halfling is actually considered a derogatory term, with Burrowman the preferred term among the race.
Burrowmen in human lands form a sort of subculture all their own. They serve their contractors well, to be sure, but few members of humanity give much thought to how, exactly, that happens. It turns out that, when out of sight of their bosses, burrowmen act entirely differently. They have their own slang, culture, economy, habits, contacts, and traditions. The majority of business in a large human city actually takes place between burrowmen, with nary a human in sight. This gives countless opportunities for skimming, cheating, bribery, graft, and outright stealing. The vast majority of illicit activity in human city is committed by burrowmen, almost all of whom are, on the surface, respectable. Those who aren't form the core of every community's thieves guild, moving unseen or, at least, unnoticed by the big folk around them. At the center of every black market, fence operation, and smuggling ring is an otherwise unassuming halfling, whose human boss assumes he is busy polishing the silver somewhere.
In addition, the countryside is crawling with so-called "Free Halflings," constantly moving from place to place in caravans of wagons. These folks make their living outside the law, as performers, freaks, fortunetellers, or whatever else they can get away with. They never settle down long enough to rile up the local guard, and provide an essential way for the local Burrowmen to move pilfered goods and currency.
Wherever you find them, all halflings have a strong cultural component regarding rules of hospitality. Guests in a halfling's home are under that halfling's personal protection, and guests are honor bound not to harm or to embarrass their hosts. Guests must be offered food and drink, as well as comfort, with no repayment expected. However, guests are expected to leave gifts when they leave to honor their hosts, even if only a note praising the host and her home. (To do fail to leave such a gift implies that the hosts somehow failed in their obligations; a grave insult.) These traditions date back even before Burrowmen joined with humanity, and are viewed with reverence bordering on the sacred.
Most Burrowman households have a family tapestry called the Legacy. The people, places, and events are woven into the tapestry using delicate, silken threads. The Legacy forms a continuous family history, sometimes going back centuries. A Legacy is passed to the youngest daughter of a Burrowman family. It is stored in a special cedar chest, tightly rolled, when not on display.
The Burrowman senses of smell and taste are extremely acute. Oddly, this seems to drive them to seek out food that is particularly sweet, sour, spicy, or pungent. A halfling's celebration commonly involves such delicacies as peppers fiery enough to burn a hole in your gut and ripened cheeses whose stink makes you gag. The halflings take great delight in the reaction of big folk to these and other dishes.
Halflings are amazing at adapting and improvising. After centuries in the lands and homes of others, they have learned to make do with whatever is at hand. An enterprising Burrowman can construct whatever is needed with nothing more than a hammer, a thimble, and some bits of string. This extends to all walks of life. If you need to figure out an alien culture, send a halfling. They have a lifetime of experience figuring out, making do, fitting in, and making good. Halflings find the silver lining of every cloud, and can turn any crisis into an opportunity.
RPGlink
Use the "Halfling" species from Dungeons & Dragons 5.24.