Discovered as an abandoned human infant in the mystical Forest of Burzee by Ak, the Master Woodsman of the World, Santa Claus was first entrusted to the lioness Shiegra. He was then formally adopted by the wood nymph Necile, who raised him among immortal beings like fairies, knooks, and ryls. This upbringing immersed him in the forest's values and wonders.

Upon reaching adulthood, Ak guided Claus to observe human society, where he witnessed widespread suffering including war, poverty, and child neglect. These experiences instilled a profound compassion for children within him. Unable to remain in Burzee as a human adult, he settled in the nearby Laughing Valley of Hohaho and began crafting wooden toys. His first creation, a carving of his cat Blinky, was gifted to a neighbor's child named Weekum. This act established the concept of toy-giving. Immortals assisted his efforts: ryls painted the toys and fairies advised on distribution.

His mission faced significant opposition from the malevolent Awgwas, who stole toys to undermine children's goodness. To evade them, Claus adapted by delivering gifts at night and entering homes through chimneys when doors were locked. When the Awgwas allied with giants and demons to escalate their interference, Ak declared war and led the immortals to destroy them, ensuring Claus's deliveries could continue.

Key traditions emerged from his experiences. Reindeer Glossie and Flossie pulled his sleigh, with their service later restricted to Christmas Eve. He placed gifts in stockings after noticing them drying by fires and decorated outdoor trees for homes without chimneys. The creation of the first Christmas tree occurred during a period of reflection late in his mortal life.

As Claus aged, the immortals convened a council to address his mortality. They granted him eternal life just as the Spirit of Death approached, ensuring he could continue his role indefinitely. Following this, he appointed deputies, including the fairy Wisk and the knook Peter, to aid his work.