Will
William James Henry, who goes by Will, is the main character in the novel. After his parents tragically die in a mysterious house fire, Will is taken under the care of the strange and enigmatic Dr. Pellinore Warthrope. Dr. Warthrope, in fact, adopts Will, who becomes Dr. Wathrope's assistant in his monster studying business. Will is an intelligent and passionate person who, despite not particularly enjoying the business in which he was forced to participate in, gives his all to everything he does. Along with Dr. Warthrope and a few friends, Will fights against the scourge of monsters that is attacking his home and town.
Dr. Pellinore Warthrope
Dr. Pellinore Warthrope is an egotistical, self-centered man who decides one day to shelter and take care of Will after his parents die in a mysterious fire that engulfs their home and killed them. This act of uncharacteristic kindness and compassion changes his life and the life of young Will. Dr. Warthrope is one of the few individuals who specialize in monstrumology, or the study of monsters. When he and Will are visited one day by a man who barges into their home with a package containing a monster, they are forced on a journey in which they will face horrible monsters.
Dr. John Kearns
Dr. John Kearns is the intelligent but exceptionally mysterious man who Will and Dr. Warthrope enlist the help of as they battle the Anthropophagi in their town. Initially, Dr. Kearns refuses the duo's pleas for help. But after he secures immunity and a hefty payment, he helps the two destroy the plague of Anthropophagi on their home and town.
The unnamed narrator
Although the narrator of the novel is never named and is not often described, they play an important part in the novel. Readers know that the unnamed narrator finds Will's journals when searching through an area one day. Intrigued by Will and his story, the narrator goes through Will's journals and tells readers about the things that Will went through throughout his life and time with Dr. Warthorpe—the strange, the normal, the paranormal, and the demonic.
Captain Hezekiah Varner
When Dr. Warthrope initially met Captain Varner, he was in an insane asylum, having been the sole survivor of a horrible shipwreck. He was a hard-working and intelligent man but was left to rot in the asylum. After Will and Dr. Warthrope enlist the help of Varner to destroy the plague of Anthropophagi on their home and town, he agrees but is killed by the demonic, cannibalistic monsters as the group battles them.
