Nice thing about a game, things can be defined and quantified well beyond the boundries of our reality.
In my game, the void is everything and nothing, the ultimate contradiction. Existince springs from and exist within the void, the void itself oblivious to anything existing at all.
Reality is like a layered onion, made of esseance. Esseance beings hypothetically exist in all locations as they are part of the esseance. Souls are a complex pattern the esseance has evolved that generates more esseance, growing the universe/itself.
The esseance is powerful and by its very nature, highly mallable and supporting of life, since it is the orgin of life. What I call Dark Essence is esseance with a reversed polarity, able to work very powerful spells, such as gate formation, summoning, undead creation, etc. Dark Esseance is not anti life, but it is the stuff of madness. Detect evil spells in my game were designed with this in mind, and they really are detect dark essence spells. Sorcerers, Necromancers and other users of dark essence are evil in the eyes of those who refrain from using it and only use natural essence, though death from fireball or suffication is still death.
Undead souls are dark essence machines, converting normal essence to dark essence, a corrupting, cold energy. Dark essence tends to twist whatever it intereacts with.
The unlife, and voidal energys, are as powerful as the "arcane" unfiltered esseance, even more so in theory. Voidal energies consume esseance and convert it back to the voidal energies from whence it came. Because of the nature of voidal energies, detect evil spells also detect unlife, though they do not discern between the deiferences of the two. This leads to great confusion.
In my game, anyone who learns to tap into the energy of the void, or the unlife, gains a new source of power. This power may be used to cast any spell the weilder knows, but only this power may be used to cast certain types of spells.
For those who just use dark essence, or essence and dark essence, there is no gain in power because the energy source is the same, it is the methodology of spell weaving that determines light versus dark essence. I do use the arcane/realms division, so there is Esseance, Dark Esseance, essence, mentalism and channeling, in a ddition to dark essence, dark menatlism and dark channeling. I make use of the handy RMCIII tables when i have "evil" spell users, with corruption points resulting in various mutations (sometimes good, sometimes not, I let the dice do the talking...and maybe some GM fiat
).
So in my game, if your warrior slaughters the village, he aint evil, just very mean, or dispicable, or whatever. The Dark magics are only weilded by the power hungry, and weilding unlife is insane. Unlife is, by its nature, truely evil to life.
lynn