While Enzo is an extremely thoughtful and keen example of his species, his perspective is limited in key areas. The first appearance of the demon zebra is telling. Enzo never considers the remote possibility that he destroyed Zoe’s stuffed animals in his hallucinatory rage. He leaps at the idea of an external force, with no credit given to the circumstances or his state of mind. This demonstrates the lengths to which he still needs to go in pursuit of human-grade introspection. By the end of the novel, his acceptance of the zebra as an internal force represents the maturity of his inward-facing eye.

Since this is a first-person narration from an unlikely point of view, there’s no guarantee that Enzo’s depiction of events is accurate. He could color the story in ways that paint Denny as a saint, and the reader would be none the wiser. No obvious hints point the way to this conclusion, but the possibility is inherent with the storytelling method.

Enzo’s development can be traced to his feelings regarding humanity. At first he envies humans, and even spites them their appendages and modes of communication. By the end of his life, Enzo realizes the value of being a dog.