Peter the Knook is a central supporting character from L. Frank Baum's works, appearing in adaptations like "Shōnen Santa no Daibōken". An immortal Knook tasked with overseeing animals, he has blonde hair, a beard, pointy ears, and green eyes, dressed in green clothes with a bell-adorned hat and brown shoes.

The Great Ak and fellow immortals entrust Peter to aid the orphaned human child Claus (later Santa Claus). He plays a significant role in establishing Claus's home within the Laughing Valley of Hohaho, transporting materials and constructing the dwelling. Peter gifts Claus a cherished black cat companion named Blinkie. As Claus matures and begins making toys, Peter assists alongside immortals like Wisk, Kilter, and Nuter, usually remaining unseen by humans due to immortal restrictions.

Peter actively participates in pivotal conflicts, notably battling the Awgwas and their Three-Eyed Giant allies. He fights effectively using spears and wields unique abilities to command animals. Following the victory, he pledges permanent service to Claus. When Claus faces aging and mortality, Peter is among the immortals guarding him. After Claus receives the Mantle of Immortality, Peter becomes one of his four principal deputies, aiding in the annual Christmas Eve toy deliveries. He adapts to challenges like smaller chimneys by utilizing his capacity to navigate tight spaces.

His responsibilities include managing the reindeer, crafting their harnesses from lion skins for the sleigh. In later traditions, he ensures the reindeer are prepared for their singular yearly journey.