In this series, several different "mythical" creatures have bonded together to form the Lore to keep themselves hidden from humans. The most active factions include the Valkyrie, the Lykaes, the Vampires, the Demons, and the Witches. Many other factions (and subsections for these factions) exist, some only mentioned in passing in select books. The IAD books are all stand-alone novels, but the subplot (a full Lore war called the Accession, which occurs every 500 years) strings through the entire series. For this, it is suggested that the books be read in order. In each book, readers meet a new couple, always cross-faction, who must overcome both their individual problems and outside forces who/that might keep them apart. Cole's universe plays on gender roles where most factions are mostly one gender (at least as far as the main characters are concerned). She also stresses that these couple are all predestined couples: the males of the factions listed above all have fated mates, though the name is different for each faction.