Wizards of the Coast. Accessed via the Libris Mortis Art Gallery here
[The last of the necromentals, and my personal favorite. The original text was very unclear about whether this was supposed to be incorporeal or not, so I split the difference at gaseous]
Voidwraith
A clot of mist flows forth like a living thing, its shape contorted
into a grimacing visage. Two tendrils grow from its center like
clutching arms.
Said by some sages to be the living embodiment of the last breaths of a
dying fiend, voidwraiths are wicked elementals composed of equal parts
air and negative energy. They are not nearly as solid as most air
elementals, but use this fluidity to creep unawares into even the most
tightly defended areas to feed on the breath of the living. Voidwraiths
are masters of hit-and-run tactics, whittling away at the life forces of
their victims before surrounding the poor soul in its airless aura to
delight in its last seconds.
Voidwraiths appear in the aftermath of storms where lives were lost. Most of Aenma’s faithful dislike them, but her evil-aligned priests are known to summon them as servants.
Shores of Swords 