Primal Energy
Primal energy, often shortened to just "primal," is unique to deities. Every deity has at least a small amount of primal, and the more powerful the deity, the more primal the deity possesses. Indeed, primal energy is the underlying basis of divinity.
Primal energy is the most fundamental energy in the universe and the most powerful, the most "raw." It can bypass all "normal" magical, physical, and mental defenses as if they weren't even there, and none of these forces can bypass a primal shield. This is not to say that primal energy is completely unstoppable—primal defenses can be worn down—but there is no normal defense against primal, and no normal attack can completely bypass a primal defense. Primal energy cannot be negated, bypassed, cancelled, dispelled, or absorbed; the only way to stop primal is with primal.
Since gods' souls are sustained by primal energy, they don't necessarily require bodies, although there are a lot of good reasons for having them. This fact, and the power of primal to change reality, means that deities are free to choose the appearance of their bodies. Abilities like sight or strength may be enhanced; new abilities may be added. Deities can spread their awareness over a wide area, gaining knowledge from many places at once. They can exert influence in a like way.
Primal energy exists in two forms, base and flux. Primal base is the form of primal energy that gives the soul divine qualities; it is almost synonymous with the deity's soul. In general, the more primal base a deity possesses, the more powerful the deity becomes. Primal flux, on the other hand, is the active component of primal energy; deities use flux in order to create primal effects. The important thing to remember is that primal base is the regenerative form of primal energy. Primal base transcends the law of conservation of energy; as such, it is a very precious commodity and deities do not use it lightly.
Primal energy controls how it engages reality; it can ignore it or affect it in ways that more "normal" means cannot. Because of this, it becomes an extension of a deity's will; through the use of primal energy, a deity can affect reality directly without having to resort to spell research, monetary expense, or any significant amount of time. However, the expenditure of primal is not a trivial matter. Deities must conserve primal for other things, such as supporting their clerics, minions, creations, and possibly less powerful gods if they so choose, doing research into their spheres of influence, and so on. An even more important thing to consider is that deities always want a reserve of flux; you never know what the day has in store.
As long as a deity has even the slightest ounce of primal base, that deity lives on. Should they have no primal base however, that deity dissipates into the void and ceases to be.
Primal Base
Primal base is primal energy in a stable form. It is what binds together a deity's soul, and the more base a deity has, the better that deity can directly affect reality. Flux generated from this base is what deities usually use to affect reality. A good analogy to use when trying to understand the difference between primal base and primal flux is to think of primal base as "principal" and primal flux as "interest;" you can spend either one, but spending primal base will decrease your principal, and therefore reduce your interest gains of primal flux in the long run. One place where this analogy fails is that you aren't allowed to "reinvest" your flux.
Since deities do not have to be in physical contact with their primal base, one of the fundamental strategies a deity learns very early is to keep a safe reservoir of primal base, possibly in several locations. Since primal base is very stable, it can easily be partitioned into separate portions; a deity might divide primal base among several planes and an artifact, just to make its destruction particularly difficult. Primal base can also be converted directly to primal flux at anytime, though given the value of base and the difficulty in procuring it, this is rarely done. When deities split up their primal base, they retain only one level of consciousness; to have multiple levels of consciousness the deity must use an ability called omnipresence. Whether or not a deity's base is split up, the flux generated by that base will always go directly to the deity, as long as the two are not separated some sort of force or shield that would stop such a transfer, such as another deity's primal flux shield.
Nothing in the universe can use a deity's primal energy, base or flux, against that deity's will. Since the deity's base and soul are inextricably combined, the deity must consent to someone else's use of that primal energy. This means that primal base cannot be destroyed or harmed in any way short of a primal attack from another deity.
Primal Flux
Clearly, primal base is a precious commodity, and is rarely used directly. The form of primal energy deities use most often is primal flux, or simply flux, which can support clerical hierarchies, setup primal-based defensive shields, and unleash "primal blast" attacks, among other applications. Though primal flux is very powerful, it has a short lifespan. It must be used within a day of its creation or it will dissipate. Primal flux serves as the physical manifestation of the deity's will. This ensures that any use of primal flux will serve the deity's will flawlessly; a primal blast will always hit its intended target, a primal shield will always protect its occupants, and a primal-enhanced spell will always be perfectly aimed. The only way to ruin this is if other deities intervene with their primal energy.
Primal Signatures
Primal energy is difficult to hide. Any use of primal energy sets up a signature unique to the deity. Deities can sense such signatures and recognize those with which they are already familiar; they are invisible to mortals. A deity is allowed to create accompanying effects with almost any primal-based ability ("a crackling red and silver streak of energy issues from Nergal's hand and echoes with the wailing of a thousand tortured souls ..."). Deities can even use such enhancements to fool mortals into thinking that another deity might be responsible for a particular phenomenon, but the signature is infallible and cannot be hidden from another deity. Note that the signature only lasts as long as the effect; there is no residual signature.
Identifying a signature is a fairly straightforward matter. If Joey visited Pele's volcano, it would be clear from the protective curse laid on the lava stones that a goddess had affected them. If he met Pele in person, it would be clear that the curse is hers, since the signature will match her primal aura. Also, just as mortal family members often share a last name, pantheons of deities will tend toward similar signatures. If Joey wanted to teach a group of deities what Pele's signature is like, the only reasonably effective method would be to grab one of those rocks and show it to them. Trying to describe a signature second-hand is rather difficult and prone to error. The best way to do this is to describe them in terms of senses. For example, Pele's signature might be "hot and red." Joey's could be "a placid calm with gentle waving," or "a rustling dampness," or something like that. For that matter, Pele could be "spiky black" or "slinky huskiness with hints of ginger," if you want to make it harder for the players to match deities with signatures. Don't get stuck on one sense, either. The examples just listed use emotion, sight, hearing, smell, touch, and taste.
Engagement
Engagement is the term for describing whether primal energy does or does not affect another force or substance. Deities can choose with which other bits of the universe their primal energy will interact. The process of setting up what a deity's primal energies will engage is called keying the primal. For example, Pele is annoyed by an incredibly foolish mortal witch. Showing unusual restraint, she keys her attack for magic instead of sending a blast of primal energy to destroy the witch. As a result, the witch is untouched by the nasty energies playing around and through her, but every magic item she has is vaporized.
Limitations of Primal Energy
In spite of the incredible power and versatility of primal energy, it is a limited resource. When a deity's flux is gone, it's time to switch to another resource or possibly die. Finally, the best way to fight primal is with primal. Primal energy may be powerful, but if an opponent has it too, the situation boils down to finesse.
