Since you always seem to be looking for new source materials, I thought you might be interested in this. It's from my notes from a campaign I was running a couple of years ago. It is widely known that the source of all magical power is an intangible substance called "mana". Mana has been exhaustively studied, but its exact nature has never been determined. It appears to be a fifth element, emanating from its own elemental plane (though the power there is so intense that mortals attempting to visit it have been instantly destroyed, and mana elementals, if such exist, have never responded to summons... a fact which most sane magicians are extremely grateful for!) Mana is an utterly intangible substance on this plane. Its behavior is completely unlike that of the other elements. Rather than exist on this plane as an independent entity, it instead permeates all matter that exists. Apparently, mana is somehow involved in the bonding force that allows normal matter to maintain its existence and coherence; the spells known as "disintegration" and the like usually operate by instantly sucking a large portion of the permeated mana from its target,. Before mana was identified and studied, it was thought that entropy, the tendency of matter to move from higher to lower states of order, was universal. Curiously, however, mana seems to exhibit "reverse entropy", tending to move from loosely organized matter (like gases) to more tightly organized liquids and solids, and "preferring" highly complex materials, such as life forms, to more chemically simple substances. Since mana is so inextricably bound to the more mundane forms of matter, it logically follows that by learning to manipulate it, one could thus manipulate mundane matter as well. This is how magic operates. Life forms, as mentioned previously, tend to collect mana from the environment, in much larger quantities than are needed to maintain the body. The beginning magician learns to manipulate the excess mana within his or her own body, using precise gestures and verbal symbols to produce "mana currents" that produce the desired effect. (This explains how an inexperienced or foolhardy mage can unintentionally kill himself with his own magic, by unintentionally exhausting the excess mana supply and depleting the mana necessary to hold the mage's structure together.) As the mage advances in skill, he or she intuitively learns the nature of these mana currents, and gradually acquires the ability to shape them directly with the mind, with less or no reliance on physical gestures. The mage also learns to directly shape the mana in the surrounding environment, reducing his or her reliance on the mana stored within the body (and thus making it possible to cast more spells in a given period). Psionics are directly related to mana as well. Apparently, the minds of sentient beings are capable of directly and instinctively producing certain precisely-shaped mana currents. In a few rare people, their specific currents happen to be in the proper configuration to produce useful effects. While such instinctive abilities allow for much less variation than the abilities of mages, they are often much more powerful and less fatiguing. Clerical magic is an entirely different case. To examine it, we must study the question of the origins of the gods and their subjects. The gods are incredibly powerful beings of pure mana. They apparently originated on the Mana Elemental Plane, though most have since inhabited other planes. With the incredible reserves of power at their command, and their intuitive knowledge of how to use it, the gods can produce effects beyond the contemplation of man. However, in so doing, they reduce their own essences by some infinitesimal (but, over a long period, important) degree; even mere survival places some drain on their power reserves. Thus, some means of replenishing these reserves must be found. It is here where the various races of our plane come in. As mentioned previously, life forms accumulate excess mana over the course of their normal activities. In the process of worshipping their chosen god, life forms effectively transfer this excess mana to that god, increasing its power. In return for this service, the god returns some of this power to its worshippers in forms more useful to them, such as the spells of clerics and, in rare cases, divine intervention. There are two major theories as to the origins of man and the gods. One holds that the gods somehow spontaneously manifested themselves on the Mana Elemental Plane (nearly every religion has its own explanation for this), and these newborn gods created the various races to serve them and increase their power (as well as to provide a battlefield for the gods' own internal disputes less damaging to the gods themselves, and to provide some needed entertainment...) The other theory, much less widely held (mostly among magic-users and others less attached to the gods), is that humans and the other races somehow spontaneously evolved first, before the presence of the gods. As each race evolved and sought out its own identity, the accumulated mana of the race combined with its subconscious desire for a racial identity, and produced a god on the Mana Plane, a god whose powers rapidly grew into the sort of god we know today. Whichever of these theories is true, this theory of mana provides answers to several previously troubling questions. For instance, theologians often wondered why many of the more exotic, magical races have no gods (other than themselves, as in the case of dragons). The answer to that, according to this theory, is that such races' own innate magical abilities exhaust the excess mana that lies unused in other races. Thus, a god exclusively devoted to that race cannot develop or survive, as its worshippers have nothing to offer it. ----- I have another paper, dealing further with the relationships between gods and earthly life, but I don't have it typed in yet. I think I'll hold onto it until after the current quest is over anyway, to make sure it doesn't conflict with your ideas.