She only appears in a flashback in Konjiki no Gash Bell Gaiden: Friend
Muumu sister

Muumu's sister and her doll


She only appears in the Muumu's flashback. she always told him that if he asked for food while facing toward the King Mamodo, he will bring food to them. But she was getting sick and died. After that, Muumu doesn't believe that the King is a good person.