White's novels cross over multiple genres. We're predominantly in the realm of fantasy—Arthurian fantasy to be exact. This means that many of the major elements of the author's source material (like Malory's Morte d'Arthur) are intact.
So, we're issuing a BOLO for magic use, fantastic beasts, and characters that are larger than life and who can accomplish feats we mere mortals cannot. Like Lancelot. He's always good for some super-human fighting abilities that probably are right up there some of the best moves in The Matrix.
But, we're also well within the boundaries of tragedy. After all, we know from the beginning (or close to the beginning) that something bad is going to happen to Arthur. There's a feeling of impending doom throughout the text, and a sense that characters like Arthur, Lancelot, Guenever, and Mordred, are locked into their fates—there's nothing they can do to escape it.
Some also have tragic flaws that contribute to their downfalls, like Arthur not recognizing his own sister (and so accidentally has an incestuous fling with her) or Lancelot being deflowered (which makes him unable to completely achieve the Holy Grail).
Finally, you can't have anything legit Arthurian without a heaping helping of romance. And by that, we don't necessarily mean those cheesy novels that are at the supermarket checkout, with the unlaced bodices and heaving pectorals. Well, there is that, of course—we're not going to lie—but we also mean romance in the medieval sense. This means a focus on chivalry, adventure, questing, and the supernatural.