Rowena is Robert's older sister, with whom Robert felt a connection from a very early age. She was hydrocephalic, meaning she was born with water in the brain. This caused her to have an adult-sized head but a body of a ten-year-old, and made her unable to walk. Robert acted as her guardian for most of his life. She was 25 years old when she fell out of her wheelchair onto the concrete floor of their barn and died as a result. Robert took it as his duty to protect her, but Robert was in his room masturbating when she fell out of her chair. Thus, he feels guilty throughout the novel for inadvertently causing her death. She remains in Robert's heart and mind throughout the novel and is constantly referenced.