• Gods of Yarth
• Metaphysics of Yarth
• Cosmology of Yarth

The Istuban Calendar of Yarth is made up of four seasons of a dozen seven-day weeks, each divided by a festival week. Years are counted from the founding of Kingtown. There are a dozen major constellations in the sky that make up the zodiac, as well as over a score lesser constellations. Other celestial bodies include Yarth's two moons, and five planets that cross the sky each named for one of the Dead Gods that some believe once created Yarth.