The House of Costayne is a massive, genial nation, ruled by Lord Tommen Costayne with an iron fist, and notable for its frequent executions and compulsory military service. The hard-working, cynical, devout population of 1.439 billion Costayneans are ruled by a mostly-benevolent dictator, who grants the populace the freedom to live their own lives but watches carefully for anyone to slip up.

The relatively small government juggles the competing demands of Education, Spirituality, and Welfare. It meets to discuss matters of state in the capital city of Three Towers. Citizens pay a flat income tax of 12.5%.

The strong Costaynean economy, worth 89.4 trillion golden dragons a year, is broadly diversified and led by the Furniture Restoration industry, with major contributions from Trout Farming, Beef-Based Agriculture, and Book Publishing. Average income is 62,125 golden dragons, with the richest citizens earning 6.7 times as much as the poorest.

Bands of adventurers rove the countryside searching for monsters, international tensions are high as Costayne threatens any government with the audacity to arrest its citizens, friendly fire incidents usually result in severe burns, and bins outnumber trees in city parks. Crime, especially youth-related, is totally unknown. Costayne's national animal is the hawk, which soars majestically through the nation's famously clear skies, and its national religion is Faith of the Seven.

Costayne is ranked 286,534^th in the world and 15^th in BFB Teams for Most Eco-Friendly Governments, scoring -4.47 on the Dolphin Recycling Awareness Index.