Domains are those spheres of influence that a god has a particular interest in and control over. They may represent abstract concepts, physical things, or elemental forces. For example, Aphrodite is a goddess of Love while Hera is a goddess of Marriage. Odin is a god of War and Magic, with Thor is a god of Strength, Thunder and Lightning.
When a god or goddess claims a domain, it is a public statement that this god represents the interests of that domain in the world and will actively promote it. A god of Magic, for example will heed to the word of magicians and sorcerers to invent and create new magical barriers and concepts. A god of Fire is promising to promote fire in the world, possibly by creating volcanoes and anything fire-oriented such as creatures and artifacts.
What IS an Active and a Passive domain?Edit
At its heart, a passive domain is something that tends to flavor actions but doesn't particularly motivate them (a water god might create water-based elves, for example). In some cases, these domains are so limiting that it seems like there is almost nothing that one can do with that domain that is clearly part of that domain (what does a moon-god do after creating a moon that is particularly moon-iful?).
In contrast, an active domain is something that, hopefully, motivates actions as well as flavors it. A god of travel might create roads, teach sailing, establish air and water currents, introduce planeswalking, etc. Such a god might flavor creations with travel as well (creating nomadic peoples, for example).
To note, none of the examples of passive domains HAVE to be passive. It is just that some things are going to be a lot harder to actively play. If you have a good reason for why a domain should be active instead of passive, let us know and chances are it will get the go-ahead. The active/passive dichotomy is intended to be a useful concept, not a restricting rule.
How does one claim Domains?Edit
Domain are gained in two ways:
The first domains that any god will have is the ones that they start with (all gods start with one active and one passive domain). These domains, perhaps more than any other domains that the character will claim, helps define what the god is.
All other domains are gained through play. A "Forge Domain" action is available to formalize a concept and a god's control over it; however, this action must be backed up through roleplaying. A god that has never done anything related to water, and never will do anything with water, should neither create nor claim the Water Domain.
Domains are not exclusive; more than one god may have the same domain. A god may choose to share a domain with another god, another god may steal a portion of it from them, or it might be ripped from a defeated foe. It is not usually allowed for another god to re-create a domain that is already in existence, but exceptions are possible if discussed in the OOC thread first. The point of these restrictions is that domains should be a point of interest and conflict: if there are two gods who control the life domain, there should be a story behind that.
Generally, two domains that cover essentially the exact same thing are not permitted. That is, if there is a already a Light domain in the game, creating an Illumination domain wouldn't be allowed as a loophole to the above. It would still be permissable, however, with discussion in the OOC.
How do Domains affect the game?Edit
Domains are abstract concepts that serve to help guide a participant’s actions in the game. These also serve to help other participants gauge what a particular god’s goals are in the game. There is no rigid, mechanical affect of domains on the game world other than fluff.
That being said, domains are a great way to flavor a god's low-level actions in the world. See the Cantrips section of the actions page for more information.
However, having a domain is like staking out your territory. Other gods are free to enter that territory (that is, do things that might fall under the jurisprudence of your domain), but doing so is essentially trespassing. Another god might become a usurper, claiming the same domain; this is effectively one god challenging another’s authority.