Dumathoin (DOO-muh-THOE-in) is the Keeper of Secrets Under the Mountain, and he hides the secrets of the earth until deserving and diligent dwarves are ready to be guided to them. He lays veins of iron, copper, gold, silver, and mithral where he feels they will best benefit his followers. He watches over the safety and security of miners of all races and has a special role as the protector of dwarven miners.

Walk the deep and silent ways of Dumathoin. Seek out the hidden gifts of the Keeper of Secrets Under the Mountain. That which is hidden is precious, and that which is precious shall stay hidden. Seek to enhance the natural beauty of Dumathoin's gifts and go with, not against, the contours of the deeps. Beauty is in the discovery and the Grafting, not the holding. Keep the places of our dead inviolate and well tended; the noble ancestor of our race will neither be robbed nor mocked through the actions of thieves and defilers. Abide not undead creatures, especially those that take the form of dwarves, thus mocking the creation of Moradin.

Clerics of Dumathoin seek always to uncover the buried wealth of the earth without marring the beauty of the ways beneath the surface or being overly greedy. They often supervise mining operations and maintain underground safety and security. They work to clean up the rubble of mining, to grow and put in place luminous fungi and edible deep-mosses, and to direct water through the earth to best serve the underlife that includes, of course, dwarves. Clerics of this faith are always hunting for new veins of ore, new sources and species of useful fungi, and new delves or underways never explored before. They try to identify encountered dangers and determine strategies to deal with these menaces of the deep places appropriately. They also bargain with other (nonhostile) underground races to avoid over-exploitation of resources.

A cleric of Dumathoin is always learning the tiniest details of conditions and life underground. Most clerics are therefore invaluable in leading companions through the underways in darkness (for example, when all torches have been used). They can also find water, veins of ore, and cracks or fissures that provide ways out, or can be mined to yield a way from one cavern to another.

As Keeper of Secrets Under the Mountain, Dumathoin is the dwarves' protector in death. While it may have been otherwise in the early days of dwarven civilization, Dumathoin's clerics have been the primary morticians and tomb protectors since the dwarves came to Wearth.. In fact, clerics of Dumathoin do their god justice as Keeper of Secrets, for it is incredibly difficult to find dwarven tombs at all, let alone plumb their mysteries.