Rahal's sister, Rania is a crafter of the flutes the dragon horses riders use. These flutes make sounds that humans cannot hear, only dragon horses can. As a result, these flutes are used to give secret signals from rider to mount.
Rania, though, is different. Rania can hear the sounds the dragon horses hear, and thus, the flutes. Because of this, her flutes work very well and gets orders piled up for years in advance.
Rania talks eccentrically, talking about the beautiful and strange sounds that many different people make, such as Cornelio sounding like DoReMi elf, and how the men's bath sounds better then the women's. Since most people can't hear those sounds, most people find Rania to be very eccentric.
Rania joins the Prince's forces and works with the Dragon Cavalry. On the eve of the final battle, the dragon cavalry members play their flutes, and Rahal allows his sister to play as much as she likes, to which she responds being in harmony is a beautiful thing. After the war, Rania returns to making flutes. She takes on apprentice after apprentice, but none of them live up to her expectations. - Matt620 (article), Basel (image)