Glenda

As Princess of the Demon World, Glenda is fiercely competitive. She immediately butts heads with Yucie, her rival to become the Platinum Princess. Glenda is a braggart who frequently proclaims herself as "fantastic" and "elegant," and is also often selfish, jealous, and temperamental. But she has a sweet side which she tries to hide, and eventually becomes very close friends with Yucie (perhaps, even overly-protective of her), even though she's loathe to admit it. Throughout her friendship with her new friends, she changes to more honestly enjoy friendship and have fun with her friends. Is seventeen, but like the others, has the body of a ten-year-old, although she looks rather developed.

(Source: Wikipedia)