Pia's pet fairy mouse. Mappy acts as Pia's bodyguard whilst traveling and the guide to the three holy artifacts. He also has a hidden ability that enables him to transform to the size of a grizzly bear at will. This tends to deter Rufa from whacking Pia when she gets on her nerves, as Mappy often whacks Rufa straight back. He also reflects his master's moods; in the anime episode two he becomes dreamy-eyed just like the girls when Dick Saucer happens to come upon them, while as a mouse he shouldn't have any interest in him. In the anime Mappy is present from the beginning, whereas the manga has him enter at the end of Volume 1.