Kirby is Ellie’s English springer spaniel and her ghost companion. Ellie has known Kirby all of her life, and when Ellie learned the ghost secret at the age of 12, she wasted no time in bringing back her best friend. Kirby isn’t just a friendly sidekick to Ellie’s adventures: He also represents Ellie’s family secret, and her connection to the underworld and her ancestors.

At the beginning of the novel, Ellie is playing with Kirby in her room when Kirby starts to behave strangely. He “turn[s] fully visible,” even though “it [takes] effort for the dead to be seen” (12). He also runs through walls and whines, and Ellie remembers how, “when [her] grandfather had a heart attack, Kirby threw a fit, as if he could sense Grandpa’s pain” (12). This detail shows the reader that Kirby isn’t just connected to Ellie but to everyone she loves and cares about. Kirby is the first one to know that something has happened to Trevor, and he is the one who alerts Ellie that someone she loves is in trouble.

Ellie also relies on Kirby for protection during times of danger. When she rides across town on her bike, she is momentarily unnerved by the stories of “clans of teenage-bodied vampires, carnivorous mothmen, immortal serial killers, devil cults, cannibal families, and slenderpeople” (14).