Each Comyn family controls part of Darkover's landmass, known as a Domain, but strategic inter-marriage and feudal land issues result in fluctuating domain borders. Each Comyn family has a gift — a family-specific laran power, though in reality, not every member of the family has the family gift. Also, a member of a family may have another family's gift, in whole or in part. The gifts may skip generations. Of particular note is that twins often have differing amounts of the family gifts. One twin usually has more of the gifts than does the other twin.