I'm sure everybody who's read more than two Oz books knows about Roquat, later known as Ruggedo, the former King of the Nomes. Somewhat less prominent in the series, but still a significant recurring character, is his replacement Kaliko. Kaliko is first introduced as Roquat's Chief Steward in Emerald City. He might also be the unnamed Chief Steward in Ozma, but that's by no means guaranteed, considering how often Roquat "threw away" his officials at that point. He's presented as obedient to his monarch, yet not afraid to argue when he knows there's nothing the King can do. Roquat/Ruggedo has a habit of throwing his scepter at Kaliko, but fortunately the Steward became an expert at dodging it. In Tik-Tok, Kaliko has apparently been promoted to Royal Chamberlain (possibly a position he managed to obtain for himself when Roquat lost his memory and changed his name), and he plays an important part as a mediator between Ruggedo and his subjects. When Ruggedo is driven out of the kingdom at the behest of the Great Jinjin, Kaliko takes his place as Nome King, and it's implied that he'll be a kinder, gentler Metal Monarch. When we see him again in Rinkitink, however, he's pretty much just as nasty as his predecessor. The literary reason for this is that L. Frank Baum wrote Rinkitink as a non-Oz manuscript that was somehow never published, so he eventually made some minor changes to work it into an Oz book. Since Kaliko had become the Nome King by this point, Baum placed him in that position in the rewritten book, even though it was most likely originally Roquat/Ruggedo. We could perhaps say that the power had corrupted Kaliko. Ruth Plumly Thompson seems to have wanted to create somewhat of a balance between the two personalities, making him devious at times, but never openly nasty. He's also a quite nervous ruler in Thompson's characterization, both fearful and resentful of Ozma's interference in his affairs.
Scepter-dodging is not Kaliko's only useful skill. He also reassembles Tik-Tok after Ruggedo breaks him in one of the Little Wizard Stories, showing a great mechanical aptitude. Rinkitink shows him working magic, but it's the only canonical book that does.
As for Kaliko's appearance, he's described as having a "fat, round body" in Emerald City, but John R. Neill usually drew him as being skinny (perhaps to present a greater contrast between him and Ruggedo), and Thompson followed suit in the text of Gnome King. And while I've heard people pronounce his name "Coleco" (like the electronics company), I'm pretty sure it's supposed to be pronounced "calico" (like the fabric or the cat). Usually, if I can find some sort of wordplay in a Baumian name, I assume it's intentional.