Domains are an expression of a god’s expertise and influence on the world. A god with fewer domains is most likely less powerful and has fewer followers than a god with many domains, by sheer amount of time spent in the world. Every god has at least one domain.
Domains come in multiple levels, each with varied degrees of specialization. The cheapest domains to acquire, lesser domains, are the most specialized and likely most commonly acquired. Any god may claim any Greater, Moderate, or Lesser domain regardless of if it has already been claimed by another god. However, each domain may only be claimed once as the starting domain of a god, and new gods may start with domains that have already been claimed (unless another god already started with that domain)
A god can share any domain he posses with another god at any time he wishes. However, the domain can be reclaimed at anytime by the original owner.
While Greater domains tend to be wider in scope, Lesser domains exert greater control over the limited element. A god of Dragons (a Moderate domain) would have more control over dragons than a god of Life (a Greater domain), but a god of Chromatic Dragons (a Moderate domain) would have greater control over Chromatic Dragons than the god of Dragons, and a god of Red Dragons (a Lesser Domain) would have greater control over those creatures than any other mentioned god.
Greater Domains are some of the more powerful domains available. They include the basic elements, concepts that are essential to civilization, and more abstract things like Time and Void. Remember, with great power comes great responsibility.
Moderate Domains are more specific than greater domains allowing for wider control over a certain aspect of existence such as weather and dragons.
Lesser Domains are the most specialized types of domains in the game, allowing the god or goddess who holds it unrivaled influence over that particular aspect of reality.
A list of Example domains of all three levels, for reference. These are by no means the only domains available. Those Domains that are wiki-linked have been already claimed; however, more than one god can claim Greater, Moderate, and Lesser domains.
Clicking on a linked domain will take you to the page of the god who has it as their primary domain. Red linked domains are owned but aren't any god's primary domain.
Aberrations, Animals, Bravery, Civilization, Conquest, Corruption, Decay, Diseases, Dragons, Dreams, Fey, Gravity, Healing, Honor, Invention, Justice, Language, Luck, Madness, Mercy, Metal, Moon, Music, Necromancy, Ocean, Passion, Pestilence, Plant, Protection, Psionics, Purification, Rebirth, Renewal, Retribution, River, Sky, Slaughter, Stars, Storm, Strategy, Strength, Sun, Travel, Trickery, Truth, Undead, Weather.
Athletics, Blacksmiths, Blue Dragons, Caverns, Chromatic Dragons, Cities, Courage, Day, Deception, Dwarves, Elves, Endurance, Envy, Evil Dragons, Fear, Fighters, Force, Forest, Gold Dragons, Greed, Halflings, Harvest, Hatred, History, Illusion , Insight, Joy, Kobolds, Lightning, Love, Lust, Machinery, Meditation, Mountains, Night, Pain, Pleasure, Poison, Pride, Revelry, Rogues, Runes, Scrying, Sea, Sight, Sleep, Song, Stealth, Suffering, Teleportation, Trade, Traps, Trees, Tyrants, Vanity, Vengeance,Victory, Wind, Wizards, Wrath