You can substitute “horror” for “dark fantasy” if you like, but fans of this sub-genre would probably be able to create sharp divisions between the two. Just as horror fans would classify different types of horror stories (animals stalking humans, humans stalking humans, humans stalking animals), so too would they make room for tales that include more supernatural elements.
Magic, occult, paranormal—to some people, these are interchangeable terms. If you have a firm idea of magic being distinct from the other two practices, you'll find less of it here than in other fantasy works. The paranormal dominates.
There is not much need for complex characters in this sub-genre, but some stories might explore difficult moral decisions.
Low levels of complexity when measured by sub-plots, twists and turns. These are meant to thrill and chill, and most of the complexity will be brought to the events by the reader according to their tastes.
As with classic movies versus today's over-produced blockbusters, the newer books eschew implied violence and revel in lots of gore. Violence and sexuality, if it exists, are closely linked.