D&D Monsters: Harpies

Harpies are one of a number of D&D monsters that owe their origins to Greek myth. However, the story is not quite as simple as that, since they actually combine two different Greek monsters into a single being: the harpies themselves, and sirens. Both were said to be creatures that were part bird, part woman, but beyond that, there is little similarity between the two in the original sources.

Although very early descriptions of mythic harpies portray them as beautiful, the great majority show them as monstrous. As is often the case, there isn't complete consistency in the descriptions of which parts are avian and which parts humanoid, although something at least resembling the D&D form is the most common. Sirens were even more variable, and some early Greek artwork shows male examples as well as females. In essence, though, it is really only the signature attack - the siren call - that copies over to the D&D 'harpy', which in other respects, is more closely based on its namesake.

D&D Monsters: Ghouls

1E

The term "undead", as used in D&D actually refers to (at least) three different categories of being. First, there are the mindless undead, such as skeletons and zombies, which are effectively automata that happen to be made from corpses, rather than from inanimate matter. Then there are what we might term the "wilful corporeal" undead, where some kind of intelligence animates the physical body of the deceased, and finally the incorporeal undead, which are a different kind of entity altogether. Ghouls belong to the second of these categories, although they are unusual in the degree of physical transformation that they apparently go through.

Ghouls are originally a creature of Arabic folklore, in which they are a kind of demon (as in the name of the comic-book character Ra'as al-Ghul) that lives in the desert and lures people to their doom in order to kill them. In the eighteenth century, this was introduced to Europeans by Antoine Gaillard, who added the additional detail that they live in graveyards and eat the dead buried there.  This has remained the standard version ever since, although with significant variation.