The Winter Warlock, called Winter for short, is a character from the Rankin/Bass Christmas special Santa Claus is Comin' to Town. He starts out as a villain, as he was once unwilling to let anyone pass and go into Sombertown or vice versa. But after Kris Kringle gave him a toy train, the evil in Winter's heart melted away resulting in him becoming good and he became a vital friend to Kris, giving him the land to build toys.
As time went on he started to lose his powers to the point where, "I can't even do card tricks." When Kris was arrested for smuggling toys into Sombertown by the hateful Burgermeister, Winter was arrested along with him and the other Kringles. He secretly spoke to Jessica when she came to is cell and together they came up with the plan to escape. They would use his last magical tool, his magic corn, to allow reindeer to fly, and would escape from the prison this way. After this, Kris, Jessica, Winter, and the Kringles all escaped to the North Pole. However, this incites the angry Burgermeister to declare not only Kris, but also the Kringles and Winter, as outlaws, until the Burgermeisters eventually died out and fell out of power. Winter had one last bit of magic to create the very first Christmas trees at Kris and Jessica's wedding. By the end of the special, it's revealed that Winter's power was back and declared that there will indeed be a white Christmas.
Strangely, in Rudolph and Frosty's Christmas in July, Winter is not seen in any of the flashbacks depicting scenes from Santa Claus is Comin' to Town.