Mercenary companies are organized by a single or small group of fighters. The organizer, or group leader, becomes the captain of the new company. If the captain has a good reputation built up among mercenaries in general, he or she will be able to recruit more members. Once a company reaches sufficient size, they only need to recruit enough to replace any losses from battle or retirement. A solid company with a well-respected captain will have the luxury of turning down unsuitable applicants.
A reputable company will register with the Mercenary Guild. This requires that they pay their annual Guild fees, and that the members adhere to the Mercenary Code. Much like the Geneva Convention, the Mercenary Code places limits on behavior in wartime in an attempt to prevent atrocities. Guild membership also gives companies a recourse to settle disputes with employers who are not adhering to their contracts.
Wherever a company builds their headquarters and winter barracks, a town usually develops, even if there wasn't one previously. These towns, such as Hawksnest or Bolthaven, generally take their names from the company quartered there. The capital city of Taymyrr, Stormhaven, was likely founded by a mercenary company.