Mama is the second novel of the "man-eater series," set in the same world and around the same time as Mimizuku to Yoru no Ou, but in a different country and with different characters (with a small cameo of the young Holy Knight).
In a country named Gadarcia, Salvador Toto is a five years old young girl born from two mages both members of the very influent Salvador family. This family doesn't care for lineage, and only for talent in the magical arts. And Toto, despite her efforts, shows almost no talent for magic. As she's worrying about being expelled from her parents house in a near future, she wanders in the depth of the Salvador's temple. There, she will meet a creature with the appearance of a little child, a demon sealed away since hundred of years. A man-eater. So frighteningly powerful that no mage ever managed to make him his familiar; and that liberating him would surely cause great disasters for the country.
This is a story of a twisted love between a lonely demon and of a young child who decided against everything and everyone to become his mama.
Second part of the story, featuring new characters a few dozen of years later who get involved with an important item related to the legend of the man-eater demon from the Mama story.