The Neveria Famiglia is a neutral family. Their boss is Aurora, the seventh boss, she is Cristal and Biancaneve's mother and she'll be the boss until Cristal will be 20 (right after the end of the second arc).
Neveria family is known as "the family of the ice" because of their territories. Alaska, where there are their headquarters, Canada, Greenland, Iceland, Norway and certain areas of Sweden, Siberia and the north pole. All Arctic lands are under their control.
Because Cristal has a sort of cerimonial robe (the one he uses when he fight) it seems that the Neveria have particular traditions to which they are bonded.
Neveria's "Neve" means snow.