https://en.wikipedia.org/wiki/Santa_Claus

Long, wide summary: "Santa" was a character of Germanic paganism, merged into Christianity and justified with the existence of Saint Nicholas, whom was ultimately forgotten as folks were taught to be consumerist pigs obsessed with worldly living.

Review "Origins."

Irving's interpretation of Santa Claus was part of a broader movement to tone down the increasingly wild Christmas celebrations of the era, which included aggressive home invasions under the guise of wassailing, substantial premarital sex (leading to shotgun weddings in areas where the Puritans, waning in power and firmly opposed to Christmas, still held some influence) and public displays of sexual deviancy; the celebrations of the era were derided by both upper-class merchants and Christian purists alike.

Review "Germanic paganism, Wodan, and Christianization"

Wodan's role during the Yuletide period has been theorized as having influenced concepts of St. Nicholas in a variety of facets, including his long white beard and his gray horse for nightly rides (compare Odin's horse Sleipnir) or his reindeer in North American tradition.

Review "Yuletide." https://en.wikipedia.org/wiki/Yule

Lastly, figure out what the Pagan Gods were. Understand what "Nephilim" means.