The Nome King is a fictional character in L. Frank Baum's Oz books. Although the Wicked Witch of the West is the most famous of Oz's villains (thanks to the popular 1939 film The Wizard of Oz), the Nome King is the closest the book series has to a main antagonist.
The character called the Nome King is originally named Roquat the Red. Later he takes the name Ruggedo, which Baum first used in a stage adaptation. Even after Ruggedo loses his throne, he continues to think of himself as king, and the Oz book authors politely refer to him that way. Authors Ruth Plumly Thompson and John R. Neill used the traditional spelling "gnome," so Ruggedo is the title character in Thompson's The Gnome King of Oz.
In Baum's universe, the Nomes are immortal rock fairies who dwell underground. They hide jewels and precious metals in the earth, and resent the "upstairs people" who dig down for those valuables. Apparently as revenge, the Nome King enjoys keeping surface-dwellers as slaves—not for their labor but simply to have them.
Nomes' greatest fear is eggs. Upon seeing Billina, Roquat is terrified, declaring that "Eggs are poison to Nomes!" He claims that any Nome who contacts an egg will be weakened to the point that they an be easily destroyed. Baum, however, strongly hints that the fear of eggs is unjustified, as the Scarecrow repeatedly pelts him with eggs at the end of the novel, causing him no apparent harm beyond stress enough to allow Dorthy Gale to remove his Magic Belt. Sally Roesch Wagner, in her pamphlet The Wonderful Mother of Oz suggests that Matilda Joslyn Gage had made Baum aware that the egg is an important symbol of matriarchy, and that it is this that the Nomes, among whom no females are seen in any canonical text, actually fear.