"But he was descended from the greatest wizard and sorcerer who ever lived in this or in any other country, and one day Ugu the Shoemaker discovered all the magical books and recipes of his famous great-grandfather, which had been hidden away in the attic of his house.

So he began to study the papers and books and to practice magic, and in time he became so skillful that, as I said, he scorned our city and built a solitary castle for himself." "Do you think," asked Dorothy anxiously, "that Ugu the Shoemaker would be wicked enough to steal our Ozma of Oz ?" "And the Magic Picture ?" asked Trot.
"And the Great Book of Records of Glinda the Good ?" asked Betsy.
"And my own magic tools ?" asked the Wizard.
"Well," replied the Czarover, "I won't say that Ugu is wicked, exactly, but he is very ambitious to become the most powerful magician in the world, and so I suppose he would not be too proud to steal any magic things that belonged to anybody else--if he could manage to do so." "But how about Ozma?
Why would he wish to steal HER ?" questioned Dorothy.
"Don't ask me, my dear.

Ugu doesn't tell me why he does things, I assure you." "Then we must go and ask him ourselves," declared the little girl.
"I wouldn't do that if I were you," advised the Czarover, looking first at the three girls and then at the boy and the little Wizard and finally at the stuffed Patchwork Girl.

"If Ugu has really stolen your Ozma, he will probably keep her a prisoner, in spite of all your threats or entreaties.

And with all his magical knowledge he would be a dangerous person to attack.