Kostolain was a planet in or near Federation space which, in 2368, was home to the Conference of Judges. Campio served as third minister to the Conference on Kostolain during the time he was to be married to Lwaxana Troi.

The culture of Kostolain was reserved and exceptionally formal. Strict protocol was always followed and, in many cases, enforced by the presence of a Protocol Master. (TNG: "Cost of Living")