In the December 1993 issue of The Emerald City Mirror, Marie Richardson (who seems to have disappeared from the Internet, by the way) had a story in which Roquat and Ruggedo turn out to be two separate Nomes. They’re brothers, and Roquat ends up trapped in Ozma’s palace after drinking the Water of Oblivion in The Emerald City of Oz, while Ruggedo is mistaken for his brother and becomes King of the Nomes. The Hungry Reader made a similar suggestion, also taking into account Ruth Plumly Thompson’s more traditional spelling of “Gnome.” It seems pretty clear that L. Frank Baum and Thompson both considered them to be the same, as Ruggedo remembers the events of Ozma in Tik-Tok (in which he’s first called Ruggedo, with the name change being explained in a footnote), Kabumpo, and Gnome King. There are some subtle changes in the Nome’s personality throughout the series, but no more than happens with any of the other characters, particularly when written by different authors. Besides, he does have his memory erased a few times, and while he generally regains it, I have to expect the Water of Oblivion would have lingering effects. When he’s disenchanted in Handy Mandy, he initially doesn’t remember his name, but does shortly afterwards. So I think there’s just one Nome with a changing name, but the idea is still clever. That got me to thinking about other Oz characters who have had different personalities. I don’t mean mental illness, but characters who have been essentially different people (or animals) at some point. The most obvious example is probably Ozma, who grew up as Tip. There have been a few attempts to bring Tip back as a separate character, and while I have nothing against the idea, I’m not entirely sure why he’s that appealing to writers. He DID have a different personality from Ozma, but is that due to the different form or because of what was expected of a princess?
Picture by Sarah Clark
There are also a few references to Ozma being hundreds of years old, sometimes even remembering things from her past life. And in Forbidden Fountain, she drinks the Water of Oblivion and takes the name Poppy, then borrows a boy’s clothes. Jack Pumpkinhead immediately recognizes her as Tip, and wonders why she’s not still a girl.
The idea that Mombi switched Ozma’s form with an actual Tip was also proposed as a possibility for the Good Witch of the North, who is revealed to be the younger Queen Orin at the end of Giant Horse. As with Sir Hokus of Pokes becoming younger in Yellow Knight, it seems like Thompson thought characters had to be young and married to have happy endings.
That said, we don’t see enough of the younger Orin or Corum to tell whether their personalities are significantly different from in their enchanted forms, and I would imagine they’re not. But then, if Orin had her form switched with the earlier GWN, they might be quite different.
Picture by Ricky the Rock Star
The Switcheroo for the GWN doesn’t explain why no one apparently thought it odd that she’d forgotten her past. Also, if the previous GWN’s name was Locasta, where did the name Tattypoo come from? According to Paul Dana’s Magic Umbrella, it’s a title for a Gillikin oracle. That’s fine, but wouldn’t people still want to call the transformed Orin Locasta? Maybe they just assumed some sort of magical accident affected her mind. I don’t think there’s any way that Sir Hokus could exist as a separate person from Corum, although I don’t know that he needs to. If he just let himself age a bit and grow a mustache, he could easily be close enough to his old self to explain why even Thompson still calls him Hokus in Yankee. One character I did think was changed for the worse was Prince Bobo when he stopped being the goat Bilbil, as his crankiness was the most interesting thing about the character.
In Royal Explorers, however, he’s still just as stubborn in human form. Some other transformed characters, like Peg Amy in Kabumpo and Pretty Good in Grampa, come across as more physically interesting but no different in personality when under enchantment.
It does seem that being transformed affects someone’s nature to a certain extent. The Shaggy Man’s donkey head in Road wants to join the actual donkeys in braying at daybreak.
The disenchanted Prince Bobo blames his former disposition on the nature of a goat. Kiki Aru in bird form automatically starts cawing, and has no trouble flying. Pajuka falls into the habits of a goose when turned into one, and still keeps some of them after being changed back.
And in Eloise Jarvis McGraw’s Rundelstone, Poco can tell time automatically after spending time as a cuckoo in a clock. There are also transformations that cause memory loss, or perhaps there’s an additional spell worked in to do this. I don’t think it happens in Baum, although maybe I’m forgetting something. By Bilbil’s own admission, he knows who he really is, but didn’t think there was a point in telling anybody. In Thompson, Corum, Peg Amy, Pretty Good, Pastoria, Orin, and Marygolden all lose their memories upon transformation, and regain them when disenchanted. Pajuka does retain his memory, but Mombi apparently worked into the spell that he’d cease to exist if he told anybody what happened, or at least the witch convinced him she did. I guess we don’t really know if there was any memory erasure with Ozma herself, since she was a baby when she was turned into Tip. Then again, Lost King does have her remember hiding in Morrow with her father.
A case of multiple identities that doesn’t result from transformation, or at least not direct transformation, occurs when the Tin Woodman talks to his old head, and finds it disagreeable. Apparently the two have somewhat different personalities despite officially being the same person. And Captain Fyter’s head becomes that of Chopfyt, who doesn’t appear to recall ever having been anyone else. And I can’t even say how the patched people on Sky Island react to having both bodies and brains mixed and matched.
VoVatia 
Boy, where do I even begin with all the contradictions… That was extremely difficult for me as I was conducting research for my first Oz Novel, The Flight to Oz Book I: Arrival, as I tend to take things hyper-literally.. I finally got to the point of using what I can and avoiding the rest. As for Ozma/Tip, I have Tip as being treated pretty badly by Mombi and in The Ultimate Act of Hearting, Dorothy goes into Ozma’s deepest memories and heals several points in the timeline-starting when Tip was 5. I agree that the Nome King is not a separate individual. In Book I, the result of the Magic Barrier being enchanted has horrific unintended consequences for Oz 120 years later. Speaking of which, Book II has the results of Ozma sending the entire army back to creating hell for Ix. (A large contingent of Nomes, Growleywogs, and Phanfasms regained their memories 15 years after “Oz couldn’t be seen anymore.”)
Here is my raw excerpt from my notes.
Lycaon is from Ix, Jonathan is a new OC from Book I and from the Earth of 2030.
Lycaon shows Jonathan, alone, a room that was used as an examination room/interrogation room during the Raiding Parties Era. In it are various weapons and several beings that have been freeze-dried and are displayed behind glass. They are two Growleywogs, one Nome, and one Phanfasm that was stuck in the middle of shape-shifting. The room is part of the underground facility.
J: “What are those things?”
L: “Beings that raided, attacked, and enslaved some of us.”
J: “For how long?”
L: “The hardest fighting lasted nearly 50 years. Large phalanx’s of them broke through the defenses of Counties Five and Nine. We were very lucky that Counties Four, Eight, and Twelve had factories. We used our rail system to provide transport for troops and weapons. This residence was both a small fortress and as you see, a way to understand them better. For about 35 years, the raiding parties stayed mostly small and attacked almost daily in Counties Five and Nine. Except…”
J: “The Great Battle that you got terribly injured?”
L: “Yes…They made one last all-out campaign. I lost many good and brave soldiers.”
J: “You haven’t had much peace here?”
L: “From when they first attacked until The Great Battle, we’ve only had twenty years of peace.”
J: “When did it all start?”
L: “Some fifteen years after Oz couldn’t be seen anymore. Just only recently have our villages in the mountains been able to see Oz through their telescopes.”
J: “The Magic Barrier…”
L: “That’s what it was called. Interesting…”
J: “Were did they come from?”
L: “From parts outside of Oz.”
J: “But why did they attack?”
L: “They and many others had initially invaded Oz, through a tunnel under the desert. They were moments away from victory over Ozma until she used her magic to create a dust storm and then had the entire invasion force drink water that supposedly made them forget their ways. She sent an entire army, fully functioning, back.”
J: “I take it that didn’t last forever.”
L: “No… Some who had cooperated better with us told us that the effects for many waned after ten years and after fifteen years they had fully regained their memories. Just like their own king regained his.”
J: “What was their reason for attacking Ix?”
L: “They had all been promised slaves and spoils from Oz. When those who had regained their memories couldn’t find Oz, they found out about us. They wanted the same…and they wanted revenge even though we had nothing to do with Oz, the Emerald City, and Ozma herself. Queen Zixi would only attend Ozma’s birthday celebrations until the start of the fighting, then she stayed and helped us all. Our technology quickly advanced to what it is now.”
J: “How many were lost?”
L: “The initial villages were totally emptied. But slowly, we managed to recover those who had been captured and enslaved in the years after. The first ones were never recovered though-about several thousands.”
Jonathan is sadly shaking his head.
Lycaon nods his head in agreement at Jonathan’s reaction.
L: “Come, there are other places I wish to show you…”
In Kabumpo in Oz the old gnome king is radically smaller than he’s ever been, at least until he gets supersized.
Yeah, I always wondered about that. Thompson had him carve his entire history into rocks, so she must have remembered his previous appearances pretty well, but didn’t recall that he wasn’t incredibly tiny? She seems to have retconned this somewhat in later books, as I think he’s said to be four feet tall in Pirates (still small, but hardly someone who would fit in a doll’s rocker), and Matiah finds regular-sized furniture in his old cave in Wishing Horse.