Dark fantasy has yet to be solidly connected to its own particular sub-genre. Stories often described as dark fantasy are therefore more likely to be "officially" placed in either the horror or fantasy genres, based on which genre the story tends more toward.

As a natural consequence, the term itself may refer collectively to tales that would more properly belong in very different genres.

Tending toward horror:

This use of the term "dark fantasy" is considered a variant of the horror genre, but is quickly becoming a genre in and of itself. The difference between the two genres is that the supernatural beings and monsters of horror, particularly vampires, are considered to be potentially sympathetic beings with human motivations. Anne Rice is among the most successful in the genre, with her "Vampire Chronicles", but other writers such as Poppy Z. Brite and C.S. Friedman have also had success. Michelle Sagara West often uses more demonic figures, as in her "The Sundered" tetralogy and her "Sun Sword" series.

There is considerable overlap between this form of dark fantasy and contemporary fantasy.

Tending toward fantasy:

Dark fantasy in this context refers to stories that focus on elements usually found in the horror genre but which take place in a setting more alike sword and sorcery or high fantasy. It may or may not take place in its own fantasy world. In this sense, dark fantasy is usually considered a sub-genre of fantasy.

The epic poem Beowulf can be thought of as a precursor to this type of dark fantasy. Grendel's attacks on the Heorot established the formula for a great many horror stories and would represent the "horror element" in this type of tale, while the character of Beowulf himself and his later deeds (such as fighting the dragon) would represent the "fantasy element".

Dark fantasy is also used to refer to "grittier" fantasy, conducted in settings which represent the brutality of the medieval period of most family, generally with a dash of supernatural horror.