Artus Cimber has kept this item in his possession for over a century. The Ring of Winter is a golden band that resizes to fit snugly on the finger of its wearer. A thin layer of frost coats the outside of the ring, which normal heat can't melt. The ring feels ice cold to the touch and initially numbs the hand that wears it, but this cold ceases to be felt by one who is attuned to this ring.
The Ring of Winter is sentient and tries to take control of any creature that wears it (see "Sentient Magic Items" chapter 7 of the Dungeon Master's Guide). If it succeeds, the ring compels its wearer to cause undue harm to everyone and everything around it, in a cold-hearted attempt to incur the wrath of enemies and bring the wearer's doom.