Who is Sister Miriam from Brother Odd and what is their importance?

A former Los Angeles social worker, Sister Miriam had once worked with troubled girls. She lost that position when some of the parents complained about the spiritual aspect of her counseling, and she was asked to leave. She found her way to the church not long after. She has a large and imposing presence and charisma to spare. While she isn't one of the few who know the truth about Odd, she suspects that he must be at least partially Irish with the amount of blarney he spreads around.