Though the novel features dozens of named characters, each with their own stories and arcs, there is one repeated figure who comes close to functioning as the antagonist for much of the novel. From the moment of creation to the final lines of the text, the presence of Melkor is felt throughout the novel. He is the embodiment of evil in Middle-earth and Valinor, responsible for much of the corruption and wrongdoing that takes place in the novel. Whether purposefully or inadvertently, he causes problems for almost every character. Even after his disappearance from the text—when he is banished into the Void—Melkor’s lieutenant Sauron steps into position of antagonist, his actions and ideologies influenced by his former master.

One of the most difficult parts of the novel is dealing with the huge variety of names that are assigned to each character. Many characters are given a name in a number of languages that Tolkien switches between depending on the requirements of the text. Melkor is an excellent example of this. While he is referred to almost exclusively as Melkor in this guide, he has a number of different names. At the moment of creation, when Eru begins to sing with the Ainur, the name Melkor is used.