Despite a cute and whimsical demeanor, Jack Frost harbors a dangerous nature. Exhibiting a playful and mischievous personality, he punctuates speech with phrases like "hee," "ho," and "hee-ho," derived from "heave-ho!" This innocent facade conceals cruelty; when angered or encountering disliked individuals, he readily employs freezing breath to fatally encase them in ice, maintaining his characteristic smile. Folklore suggests his original form was a more fearsome abominable snowman, with the current snowman-like appearance adopted as a strategic ploy to appear approachable and facilitate freezing.

Within the *Devil Children* narrative context, Jack Frost assumes an antagonistic role. An army of Jack Frosts orchestrates the kidnapping of a protagonist's younger brother, transporting him into the demon world and directly instigating the core story conflict. He is recognized as part of an extended "Frost" family of demons, including variants like King Frost, Black Frost, and Pyro Jack. Black Frost represents a corrupted evolution occurring when Jack Frost's ambition resurfaces latent demonic traits. This family shares his linguistic quirks and association with cold.

Visually within *Devil Children* media, Jack Frost's design underwent modifications to align with the series' distinct aesthetic, differing from portrayals in other franchise branches. These adjustments typically involved simplifying features while retaining core elements like his snowman silhouette and winter attire.