Kringle

Kringle, or Santa Claus, is is a wyldfae. He first makes an appearance in Cold Days.

Description
Kringle is a wyldfae associated with the winter season, and thus considered the Winter King.

In the Series
In Cold Days, Harry Dresden is first introduced to him at Mab's combination Birthday party and coming-out party for the new Winter Knight.

In Mythology
Santa Claus is believed to be based on the merging of the myths of Saint Nicholas of Myra and the Legend of the Norse God Odin. It is strongly implied that within the Dresdenverse, Odin is still active and is now known as Donar Vadderung, a very powerful being and CEO of Monoc Securities. In Cold Days, Kringle reveals that the Winter King may be another Mantle, worn seasonally by Odin.

Word of Jim
According to Jim Butcher he is kind, the spirit of generosity in a time of bleakness.