King Koopa appears across three distinct fairy tale adaptations within this anime series, each portraying him in a different antagonistic role within self-contained narratives. In the first adaptation, inspired by Momotarō, he commands a band of oni from their island fortress, kidnapping a young woman tied to the protagonists and demanding her as his own; the hero and allied creatures defeat him through direct confrontation. The second adaptation, based on Issun-bōshi, casts him as a menacing oni who invades a kingdom to forcibly marry Princess Peach; a miniature hero defeats him by attacking internally with an improvised needle weapon. The third adaptation, reimagining Snow White, presents him as a gender-flipped evil queen obsessed with being the "fairest," consulting a magic mirror for validation and poisoning Princess Peach out of envy; this incarnation uses magical assaults and minions in the climactic battle.

His strategies consistently rely on deploying minions—primarily the Koopalings—to advance his objectives, though their functions fluctuate between stories, serving as direct accomplices or proxies for characters like huntsmen. Motivations adapt to each narrative, shifting from villainous infatuation and forced marriage to vanity-fueled malice. He wields magical artifacts such as the Snow White tale's mirror and exhibits physical traits including blue eyes, a departure from his typical depictions in other media.