In Advanced Dungeons and Dragons, beginning with the First Edition's Monster Manual II, an alu-demon is a female half-fiend. Designed as a counterpart to the cambion, the alu-demon is said to be the offspring of a mortal male and a succubus or other female demon (tanar'ri). While this does not accord with the tradition folklore of incubi and succubi, it does provide yet another monster with an appearance superficially like that of a beautiful woman. Specifically, alu-demons are described as appearing essentially like attractive human or half-elven females, but with a pair of vestigial bat-like wings (readily concealed beneath a long cloak). As with cambions, this description is not constant.

In the 'tidier' Second Edition, alu-demons were known as alu-fiends. Third Edition groups them all together under the heading 'half-demon'. In Planescape, they might arguably have been regarded as tieflings, but the new edition seems to suggest that a tiefling is less than half a demon.