Empire of Lightrune
Within Lightrune, there are many of the creatures familiar to players of Pathfinder and similar systems. However, some are subtly different or have been more radically altered.
Drow: Drow are no longer a true subspecies of elves. Rather, drow are elves who undergo a ritual involving the sacrifice of other elves that gives them, amongst other things, true immortality (rather than the simple extreme longevity of normal elves).
Drow are identifiable by their white hair: no effect, mundane or magical, short of shaving it off entirely or making it invisible can alter the appearance of their hair. This includes polymorph spells: if a given form that a drow can shapechange into does not have hair, it either grows an appropriate thatch or receives white colouration in some other way.
Drow are hated amongst elven communities: beyond the initial sacrifice, drow must make continual sacrifices (at a rate of about one a decade [depending on the sacrifice] to start, increasing in frequency as the drow ages) to maintain their youth. Drow may sacrifice elves, half-elves, or other drow in this manner. Magical prowess and pure elf-blood are considered the two most important criteria for a sacrifice.
Only full elves of caster level sixth or higher can attempt this ritual. Success earns the elf the ability modifiers, spell resistance, and spell-like abilities of the Drow Noble. These ability modifiers replace the normal elven modifiers, and the elf retains all other elven racial traits. Those who fail the ritual become Driders.
Drow rarely form communities of their own. Occasionally a group will manage to subvert an elven community, using them as breeding stock for sacrifices. Even more rarely, a drow couple will produce children. These children are not drow at all, though they are usually groomed to become drow at the earliest possible opportunity, or to become sacrifices.
Lich: Liches in Lightrune are creatures driven by a thirst for knowledge that rivals that of a vampire’s for blood. This is not merely metaphorical: the arcane workings that bind a lich’s soul to his undead form drive the lich to seek out more arcane power. While younger liches may still have other goals (temporal power, revenge) eventually all these goals are driven out by the need to amass more and more magic to themselves. This comes in the form of magic items (whose dweomers are sometimes consumed by the lich to fuel its own existence), and new spells (learning a new spell binds a lich closer to his physical form).
If a lich goes for too long without learning a new spell or consuming a magic item of appropriate power, it either dissipates into true death, or (if powerful enough) it can collapse into a demilich. The demilich ceases trying to amass magical power: rather it now consumes souls to fuel its existence. A demilich is cunning, but will be almost always brought down by its need to feed on souls. A quick reign of terror followed by being ended by an appropriately powerful champion of good is the common fate of a demilich. Those with no source of souls to feed on, on the other hand, will fall into a dormant state until awakened by the presence of other creatures.