The many of the works in this universe are set in space, and are usually described as space opera, while those set on planets can be seen as planetary romances. Works such as Cyteen and Downbelow Station are also regarded as hard science fiction. The "Company Wars" novels and the Faded Sun trilogy concerning the Mri Wars are examples of the military science fiction subgenre. The Merovingen Nights series takes place on a single planet and features swashbuckling heroes and low levels of technology, and as such might be classified as science fantasy, borrowing elements from the historic sword and planet subgenre; this is also true for the Morgaine Cycle books, set remotely in time and space from the main sequence. Unlike most works in this universe, the novel Voyager in Night also borrows elements from horror fiction.
