There are several examples of how demons have been employed in contemporary and urban fantasy. Though not as popular as vampires, zombies and various species of lycanthropes, demons are still quite useful as powerful hitme . . . hitbeings, and may play a larger role at times, too.
In Jim Butcher’s popular Dresden Files (and yes, I am a fan), there is only the occasional use of demons. When they do appear, however, the system Mr. Butcher uses appears to be a modification of the Solomonic tradition. There is an important emphasis on the magic circle and the use of true names, though the latter is an important features of the series and does not relate only to demonic beings. The use of a magic circle seems to be very important. Crossing the circle, breaking its physical barrier, is enough to ruin the protection it provides, thus releasing the demon. The demon is generally unhappy at having been summoned in the first place and, well, they’re way bigger than most humans, even full-blown wizards. Goriness typically ensues.
Kelley Armstrong’s Women of the Otherworld series (and again, yes, a fan), employs demons differently. First, they are more active in the world. Some of the series main characters are half-demons, expressing some sort of power depending on the kind of demon their father is and how powerful he is. Ms. Armstrong also divides demon-kind in two groups, one evil and one . . . not actively evil: cacodemons and eudemons. As with the Solomonic system, there is also a hierarchy of demons, given the titles of human nobility. These titles, rarely used, are related to their overall power of the demon, which is transferred to a certain extent to their human-demon hybrid children. Perhaps most interesting, though, is that Ms. Armstrong has used, in at least few occasions, the name Aratron, one of the “Olympic Planetary Spirits” from the Arbatel of Magic. Though not considered a demon per se, that doesn’t really matter, as Ms. Armstrong presents Aratron as one of the most powerful of eudemons, which fits the Olympic spirits fairly well.
Finally, though it predates either Dresden Files or the Women of the Otherworld, is James Blish’s The Devil’s Day. This story is about a munitions mogul who is looking for the next big thing. He finds it in the form of demonic evocation. After hiring Theron Ware to summon a demon to assassinate a rival, Blish’s main character contracts Ware to summon every major demon in hell and let them loose for a day to see what happens. The result, of course, is Armageddon, with the win going to Satan, who now has to be God, whether he wants to or not.
Mr. Blish’s uses of Solomonic demonology is quite literal, and he derives his rituals and demonic descriptions from several medieval grimoires. His approach to the nature of the Goetic spirits and their hierarchy is taken verbatim from the grimoire tradition, resplendent in its Christian overtones. In this Mr. Blish’s demonology is far more conservative than than either Ms. Armstrong’s or Mr. Butchers, neither of whom, or instance, have a particularly religious overtone to their demonology. Where Mr. Blish’s demons are fallen angels, those of Mr. Butcher and Ms. Armstrong’s are simply very powerful, frequently, but not always, very evil, other-dimensional beings. We call them “demon” more out of reflex than accuracy.
Demonic evocation is a nearly untapped area in the genre today. These three examples demonstrate the variety of ways in which demons can be employed in contemporary and urban fantasy. With a deeper knowledge of classical demonology, the writer can create a realistic presentation of demons and evocation that can fit into almost any contemporary fantasy worldview.