The Ancient Ones, called the Anganach by the folk of the region, represent the elder gods. Whether they preexisted in the forests, swamps, and old streams of the land, or whether they were brought with the first humans, few can say. The humans who founded Ironguard Motte, Helix, and Bogtown (called the Second Settlement by local sages) found protection in the worship of Silvanus (Green Man), Herne the Hunter, Cromm Cruach, Impurax, and to a lesser extent, Nergal.

Through respect and reverence for the wilderness and its deities, the human settlers learned to survive and established their villages. With the migration of the new gods from the civilized kingdoms to the east, the Anganach are in decline.

Some believe the following gods preexisted in the forests, swamps, and streams of the land: Silvanus (Green Man), Cromm Cruach, Herne the Hunter, Valdghar, Malachai, Nergal, and Impurax. Others believe the first nomadic humans brought their gods with them. No one knows for certain.

The New Gods, called the Futurus, include the faiths of St. Ygg, Imperiosa, Oghma, and Arcantryl, as well as the more clandestine cults devoted to Orcus and Set. Slowly their priests have made their way to the duchy.

The various deities of demi-humans (elves, dwarves, halflings, gnomes) form a third point in the triadic pantheon. Known by sages as the Du'mal, these gods aren't worshipped as widely as the Aganach and Futurus in the surface realms, but hold sway almost entirely in the Underdark.

The clerics of St. Ygg have been aggressive in their attempts to convert the people from the "primitive" faiths of Silvanus and Herne. They established a stone temple at Ironguard Motte, converted the Ironguard family, and began to spread their influence from the major trade and political center of the district.

Although the cults of Orcus and Set are not openly worshipped their influence has started to grow in the dark corners of the region.

With the founding and growth of the population of Threshold, new religions sought to expand into the Southern Reaches. These faiths are called the New Gods or the Futurus. The church of St. Ygg has been the most aggressive in establishing itself in Threshold and The Prelacy of Middenmark. The church has been less successful in more peripheral, and more traditional, regions like The Duchy of Aerik. The clerics of St. Ygg are dismissive of the Ancient Ones and position them as backward, primitive, and irrelevant. In addition to St. Ygg, the followers of Arcantryl have also established churches and followers. However, they are less aggressive than the priests of the Red God.

Despite the success of the New Gods in The Red Prelacy, local people still consider it a good omen to wander across the face of the Green Man carved into a great tree or rockface in the wilderness.

Beyond the Anganach and the Futurus, there are stories of "foreign" religions including Caer Tomhas the God of Time and Death or Omari the God of Sky and Stars.