Grandfather Frost and his granddaughter, the Snow Maiden (Ded Moroz and Snegurochka).
Grandfather Frost is the Slavic equivalent of Santa Claus - he is very popular in Russia and brings gifts to children on New Year’s Eve. From Wikipedia:
"The earliest tales of Ded Moroz presented him as a wicked and cruel sorcerer, similar to the Old Slavic gods ‘Pozvizd’ — the god of wind and good and bad weather, ‘Zimnik’ — god of winter, and the terrifying ‘Korochun’ — an underworld god ruling over frosts. According to legend, Ded Moroz liked to freeze people and kidnap children, taking them away in his gigantic sack. Parents were said to have to give him presents as a ransom in return for their children. However, under the influence of Orthodox traditions, the character of Ded Moroz was completely transformed, later adopting certain traits from the Dutch Sinterklaas (or Saint Nicholas), the prototype of Santa Claus. [ ]
Following the Russian Revolution, Christmas traditions were actively discouraged because they were considered to be “bourgeois and religious”. Similarly, in 1928 Ded Moroz was declared “an ally of the priest and kulak”. Nevertheless, the image of Ded Moroz took its current form during Soviet times, becoming the main symbol of the New Year’s holiday that replaced Christmas.”