According to the novel's magical premise, knowing someone's given name gives you a limited amount of power over them. China Sorrows knows Stephanie's name, and uses this knowledge to prevent Stephanie from rescuing Skulduggery. Stephanie is thus forced to take on the name Valkyrie Cain. Taking this name seals her given name, keeping others from controlling her, and breaks China's hold on her, allowing her to save Skulduggery. Although known as Valkyrie by other characters from this point onwards, Landy continues to refer to her in the third-person as Stephanie in the first book, and Skulduggery chooses to call her Valkyrie. However, for the rest of the series, she is known as Valkyrie.