* Matthew: A young boy growing up in the early 20th century in a poor, industrial town. He works in a forge, a dangerous and grueling job. He is struggling with the harsh realities of his life, including poverty, violence, and loss. He is a complex character, both strong and vulnerable.
* Rose: Matthew's sister, a spirited and independent girl who dreams of a better life. She is fiercely protective of her brother and often tries to lighten the burden of his struggles.
* Mama: Matthew and Rose's mother, a hardworking woman who is trying to keep her family afloat in difficult circumstances. She is a source of strength and love for her children.
* Papa: Matthew and Rose's father, a man who struggles with alcoholism and the pressures of his life. He is a source of both pain and occasional moments of tenderness for his family.
While these are the primary characters, the book also features several supporting characters who play important roles in shaping the story, including Matthew and Rose's friends and neighbors, as well as other workers at the forge.