Theo is a kindly English pastor, who loves God and loves teaching His Word to children and their families around the world. He lives in a cottage in the Cotswolds along the River Coln with a group of animal friends, using these as inspiration and springboards to teach his Bible lessons.
Luther is a mouse friend of Theo's. He is the "everyman" character of the series; that is, he looks at life from a somewhat worldly (albeit ignorant) point of view. He provides much of the pathos and comic relief in the series.
Our lovable mouse friend of Theo's. He is the most childlike character of the series, and represents attitudes and questions of young people (adults too). He is really the character that most children will identify with, as they are much like him.
Bayley is a perky bluebird that loves to sing along with Theo. She is a sometime foil of Luther and Belfry, acting like an older sister when they get into trouble and often scolds them.
Scratch the cat is primarily an adversary of Luther and Belfry. He is "like a roaring lion seeking someone to devour," and, so, a type of Satan, or Old Scratch of English literature.