The Carrans are an advanced society originating from & overseeing the trade hub world of Carr, more commonly known as 'Underworld.' Due to the wide reach of their trade, they are known by a variety of names; Carran is the most common and derived from the term for their homeworld, but they refer to themselves as the Ornha.
Carr possessed enough resources to build a spacefaring civilization from, but nothing of particular note. However, Carr was located on the convergence point of several subspace corridors forming a network much like the Underspace tunnels of the Delta Quadrant; perhaps it is the exact same network, though if it does connect to the Delta Quadrant, it has not been observed to do so yet. The Carrans explored these Alpha and Beta Quadrant tunnels and through their use, was able to connect various civilizations in trade. This naturally caused Carr to become a major trading centre, and the Carrans prospered.
Modern Carran society is highly developed, though tempered through a culture of contract based trade which is enforced with extreme prejudice. Almost anything is permitted on Carr as long as a contract is signed between two consenting parties, which had led many to use the world to conduct otherwise illegal business, earning it the name 'Underworld.' Signing a Carran contract can often be dangerous, as the parties only have to consent to the contract and not necessarily understand it fully during the time of the signing. As a result, it is possible to be tricked into unfair deals or even sign oneself into indentured servitude if one is not careful, and the Carrans will enforce the contract until fulfilled. Travelers to the world are often warned to pay attention to every detail of a contract.
The Carrans themselves are neutral; while certain Carrans run or affiliate themselves with corporations, the Carran Trade Commission (CTC), the closest thing to a government on Underworld, oversees the Carran Contract Enforcement (CCE) and ensures any contact signed under the witness of the Commission is honoured without bias for either party. The CCE have an armada which they primarily use to chase down contract violations outside Underworld, and with their knowledge of subspace corridors and network of trade contacts, it is extremely difficult to elude them.
Another prominent Carran organization is the Carran Courier Service. These Couriers deliver cargo, from supplies to people to even small ships, using subspace corridors. Usual contract rules apply to the Courier Service, which means that a contract can be signed to deliver anything regardless of legality, as long as it is logistically possible. Some make use of the Couriers for legitimate purposes, but as a ship using subspace corridors is invisible in normal space, many employ the Courier Service for smuggling.