Who is Helena MacDonald from A Sparrow Falls and what is their importance?

Helena is the wife of Fergus MacDonald. She is in her early thirties and still good looking with fine cheekbones and dark eyes that radiate intelligence. She is sure of herself and uses her hands to emphasize her speech. Her hands are strong, the fingers tapered gracefully ending in short and well kept fingernails. Her short hair is dark brown and full of curls, and she is well aware of her sexuality and how to use it. Her skin is creamy olive colored and her breasts are large for her slim frame. She smokes cigarettes, which is uncommon for women in this time period, and her first and second fingers are yellowed with nicotine.