Vesper makes the maps and charts that every ship on the Logathriad Sea steers by, and the names on Rann's most accurate maps of the world are theirs. They have made them for about thirty years.

Vesper goes out for months and comes back with a new chart. Their books carry distances, depths, landmarks, and headings. Most ports have someone who claims to have met Vesper, and the accounts differ in the details.