The clerics who inhabit the wastes of Athas are very different from those of a standard D&D campaign. They do not pray to patron deities, for they have no deities. Clerics beneath the dark sun pledge themselves to the very powers that dwell on the elemental planes. Like the Athasian deserts, the elemental powers are neither benevolent nor malevolent, caring only that their natural forms are preserved in the material world. To preserve what they can in a dying world, the elements forge pacts with a select few beings and through them hope to replenish a decaying planet to the ancient, carefree days of power.

The clerics who do the elementals' bidding are a strange and varied lot. Some teach crop rotation in order to protect and restore the earth of the harsh planet. Others command the power of flame for little more than vengeance’s sake. Whatever their motivations, each cleric is bound and sworn to preserve her patron element in the physical world. Few ever renounce the solemn agreement: to forsake the Pact is to incur the wrath of beings who possess the raw power of the elements.

Use the defaults from the Player's Handbook or Xanathar's unless changes are mentioned below. From any other book please check with the DM.

Clerics who make pacts with the Plane of Air are perhaps the most misunderstood of all the elemental clerics. They are wanderers, diviners, travelers, and mystics. Like the winds, their minds are constantly wandering, and they rarely seem focused on a current problem or situation.

Air clerics prize freedom over all. They loathe restriction in movement, personalities, beliefs, practices, clothing, and any attempt to impose limitations. This makes them enemies of bondage and slavery. The growing power of the sun has made the air angry, dry and lifeless, unable to power hurricanes and typhoons. Air clerics are obligated to protect earth and water in the hopes mighty forests might sway again and raging oceans fill the silt basins, bringing back unbridled freedom.

Air can be destructive and powerful, but it also can distract and obscure. Choose either the Tempest or Trickery domain from the PHB, adjusted as follows:

Closely tied to nature, earth priests understand the true nature of the cycle of life. When something dies, its organic material is returned to the soil to provide life for another, and in another form. Therefore, the earth clerics. outlook on life is a utilitarian one. The death of a comrade, though tragic, is simply one stage in nature’s endless chain of creation and annihilation.

Because air, fire, and water all depend on growing things for their enrichment, and because earth alone must sustain itself, it is the earth clerics who must carry on the burden of preventing the environmental holocaust looming over Athas, such as teaching proper agricultural techniques and slaying defilers who would turn usable elements to ash. For, if they do not preserve the land, will not the death of Athas weigh upon their shoulders?

All things return to the earth and all elements are dependent on the earth. This gives Earth clerics diversity in their selection of powers. Choose from the War, Nature, or Grave (Xanathar) domains, adjusted as follows:

Fire is the feared domain of destructive power, rarely seen as nurturing and life-giving. Most fire clerics are impulsive and destructive like their element, and seen as madmen who randomly destroy precious organic material. Yet, fire wipes away the old so the land can grow back stronger. They sometimes jest “to destroy the world is to destroy the defilers,” and no one is quite sure if they are truly joking.

Fire clerics are expected to preserve Athas so it can be destroyed again and grow back stronger. They encourage the growth of forests, cities, and fields. This pact leads them to directly oppose all defilers and sorcerer kings, but their ways are too eccentric to form lasting alliances with druids, who share the same goal.

Fire is a destroyer and creator. Choose from the Light (sun) or Forge (Xanathar) domains, adjusted as follows:

Water is the rarest of domains, life-giving and life-taking, with a severe and unforgiving animosity to any who would defile a well or plants. Clerics of water instinctively sense a duty to perform an age-old function of being healer and bringer of life regardless of the morals of the target, and they bear a sadness to the moisture that has been lost by defilement. Some eventually go insane, consumed by the thirst of this land and an inability to quench it. They worship by finding the dew of the morning and encouraging it, or keeping the lifeblood from needlessly spilling onto barren land (if it falls on fertile land, that is another matter). Because water can be found in all living things, they have access to powers that can restore, or manipulate, beings. Water nourishes and is a part of all beings. Choose from the Life or Knowledge domains, adjusted as follows: