The most frequently recurring villain in the Oz series is Ruggedo, originally known as Roquat, the former Nome King. I would imagine L. Frank Baum didn’t intend to use him so often, but ended up finding him convenient for several different plots. Also, by the time he penned Roquat’s first appearance in Ozma of Oz, he had already utilized the same basic scenario in other works. His manuscript for King Rinkitink, which he later converted into Rinkitink in Oz, presumably had Prince Inga trying to rescue his parents from the Nome King, and possibly actually succeeding without help from Oz. We don’t know whether Baum had a name for this king, nor can we be sure he had started using the spelling of “gnome” without the G (he spelled it the traditional way in earlier fantasy stories). His unproduced play “Prince Silverwings” had a villainous Gnome King named Kwytoffle. And the idea of people being held in underground kingdoms was pretty common in fairy tales around that time anyway, as seen in George MacDonald’s The Princess and the Goblin and Eva Katharine Gibson’s Zauberlinda, the Wise Witch. So perhaps it was a given that such a scenario would eventually show up in the Oz books, but how did he become such a fixture? Well, when Baum attempted to end the series with Emerald City, he used Roquat’s attempt at revenge on Oz as a major plot point. When he returned to writing the series, he used the character in three more works: the Little Wizard Story “Tik-Tok and the Nome King,” Tik-Tok, and Magic. Tik-Tok was actually an adaptation of a play that copied a lot of elements from Ozma, and for some reason Baum decided to use his name from the play, Ruggedo. Fortunately, he had an explanation for the name change, as the King had lost his memory at the end of Emerald City. I like the name Ruggedo better anyway; it rolls off the tongue more easily. For what it’s worth, the Little Wizard Story didn’t call the character by name at all. And the rewritten Rinkitink went along with Ruggedo’s being dethroned at the end of Tik-Tok by making the Nome King his successor Kaliko, although he acts totally differently from how Kaliko is portrayed in other books.
At the end of Magic, Ruggedo is made to drink the Water of Oblivion for a second time, and given a place to live in Oz. Ozma’s rationale is that he only relearned his wickedness because he returned to the Nome Kingdom, so this should reform him for good. Ruth Plumly Thompson, however, disregards that in Kabumpo by simply stating the water wore off. The Ozites apparently don’t expect this to happen (and that includes Glinda, who is credited with having created the Forbidden Fountain), so I wish Thompson had given more in the way of explanation. The best fan theory I’ve heard is that he’s built up a tolerance to it.
Mind you, that makes his being made to drink the Water of Oblivion AGAIN at the end of Gnome King pretty pointless, and when Thompson uses him again in Pirates, his memory seems to be fully restored.
In total, the character appears in four Baum Oz books (five if you count the Little Wizard Stories as a book) and four Thompson ones. His last canonical appearance in Handy Mandy has him turned into a cactus by Himself the Elf.
While none of the other Famous Forty authors used Ruggedo in their books, he is quite popular with fans. He appears as a villain several more times, and a few writers tried to get him to reform for good. It’s certainly possible to sympathize with him to a degree, as he didn’t start making plans to conquer Oz until after Dorothy took his Magic Belt. A few books have the Nome regaining control of the Nome Kingdom, usually temporarily but sometimes seemingly permanently.
While some of these books do strive for consistency with each other (Atticus Gannaway’s Wonderful Journey, for instance, starts with Ruggedo in the ice sculpture form that was forced on him at the end of Greg Hunter’s Enchanted Gnome), it’s pretty much impossible to form a consistent picture of the Nome King’s post-FF activities without contradicting some tales. Most more recent stories start with Rug as either a cactus or a wanderer, and sometimes he just shows up with no real explanation. In the last Oz book I read, Kim McFarland’s A Refugee in Oz, he once again takes control of the Nome Kingdom after Kaliko takes pity on him and allows him to live there. In a way, as much as I respect continuity in my Oz stories, it might actually make the most sense not to get bogged down in explanation when bringing in Ruggedo as a character. I guess it’s sort of like Sideshow Bob’s appearances in The Simpsons. The first few episodes that used him took care to pick up where the last one left off, but now they tend to minimize the explanation and just have him show up when they need him.
I’d still like to use Ruggedo in one of my own Oz stories. Actually, I already have in two of my short stories from high school, “Ruggedo and the School of Magic” and “Alliance of the Elementals”, in which I attempted to tie up some loose ends in the Nome’s adventures. I also started a longer manuscript that involved Ruggedo being partially disenchanted and ending up as a mobile cactus, only to later learn that Chris Dulabone had already used that idea in The Deadly Desert Around Oz. I have some other ideas for things to do with him, but I’ve been so lax on my fiction writing as of late (writing fictional stories, that is; I’ve been doing plenty of writing ABOUT fiction) that it’ll probably be a few years before I even start working with the former king.