The name Old Nick originated from Saint Nicholas, the bishop of Myra. For several hundred years, circa 1200 to 1500, St. Nicholas' legend took on some aspects of pagan deities, like the Roman Saturn or the Norse Odin, who appeared as white-bearded man and had magical powers like flight. Does that sound familiar?
After the Protestant Reformation in the 1500s, some saints including Nicholas were disenfranchised. Later, the Germans created figures based on Nicholas, not as a saint but as a threatening Ru-klaus (Rough Nicholas), Aschenklas (Ashy Nicholas), and Pelznickel (Furry Nicholas) who expected good behavior from children or suffer consequences like whippings or kidnappings. Does that sound familiar?
In Catholicism, St. Nicholas was assigned to be the patron saint of children. However, his alter-ego punished bad children by whacking, stuffing them in a sack to take them away. Parts of Germany and Austria called that alter-ego Krampus who carried whips to beat children. Krampus was created as a counterpart to kindly St. Nicholas, who rewarded children with sweets. Krampus, in contrast, would swat wicked children, stuff them in a sack, and take them away to his lair.
Krampus is said to come from Norse mythology, the son of Hel, legendary beast who shares characteristics with other demonic creatures in Greek mythology. Later, the Catholic Church forbade celebrating Krampus, not because it was pagan or devilish, but because the World War II fascists an ally of the Catholic Church “found Krampus despicable…creation of the Social Democrats.”
In 1821 an anonymous poet shaped the modern Santa, associating him with Christmas by adding the magical gift-bringing of St. Nicholas. That figure brought gifts to good girls and boys, but also had a birch rod for corporal punishment typically used on the child’s buttocks, back and/or shoulders. Santa's wagon, back then was pulled by a single reindeer. In 1822 Clement Clarke Moore wrote published anonymously the next year, describer the “jolly Santa … rides a sleigh driven by eight familiar reindeer.”
In the late 19th century, the image of Santa became dressed in red with white fur trim, venturing out from the North Pole in a reindeer-driven sleigh but still keeping an eye on children's behavior. “The jolly, chubby, grandfatherly face of this Santa was largely created by Thomas Nast, the great political cartoonist.”
Saint Nicholas does not appear in the Bible. Krampus is a pagan creature. Clement Clarke Moore is not a writer in the Bible. Thomas Nast is a cartoonist not religious. Thus, the Merriam-Webster dictionary defines Old Nick as a name of the devil, synonyms are archfiend, Beelzebub, devil, fiend, Lucifer, Satan, serpent.