Winter's Heart

The demigoddess of the Northern Winds holds the power of Winter's Heart. 

Nondetection. The bearer of Winter's Heart defies attempts to magically locate her and can not be targeted by any divination magic or perceived through magical scrying sensors.

Frozen Time. The bearer of Winter's Heart does not age naturally. This does not protect from magical or supernatural aging effects.

Cold Immunity. The bearer of Winter's Heart has immunity to cold damage and dosen’t suffer any ill effects from extreme cold (see chapter 5 of the Dungeon Master’s Guide).

Magic. Winter's Heart has 12 charges and regains all its expended charges daily at dawn. The bearer can expend the necessary number of charges to activate one of the following properties:

• You can expend 1 charge as an action and lower the temperature in a 120-foot-radius sphere centered on a point you can see within 300 feet of you. The temperature in that area drops 20 degrees per minute, to a minimum of –30 degrees Fahrenheit. Frost and ice begin to form on surfaces once the temperature drops below 32 degrees. This effect is permanent unless you use the ring to end it as an action, at which point the temperature in the area returns to normal at a rate of 10 degrees per minute.
• You can cast one of the following spells (spell save DC 17) by expending the necessary number of charges: Bigby’s hand (2 charges; the hand is made of ice, is immune to cold damage, and deals bludgeoning damage instead of force damage as a clenched fist), cone of cold (2 charges), flesh to ice (3 charges; as flesh to stone except that the target turns to solid ice with the density and durability of stone), ice storm (2 charges), Otiluke’s freezing sphere (3 charges), sleet storm (1 charge), spike growth (1 charge; the spikes are made of ice), or wall of ice (2 charges).
• You can expend the necessary number of charges as an action to create either an inanimate ice object (2 charges) or an animated ice creature (4 charges). The ice object can’t have any moving parts, must be able to fit inside a 10-foot cube, and has the density and durability of metal or stone (your choice). The ice creature must be modeled after a beast with a challenge rating of 2 or less. The ice creature has the same statistics as the beast it models, with the following changes: the creature is a construct with vulnerability to fire damage, immunity to cold and poison damage, and immunity to the following conditions: charmed, exhaustion, frightened, paralyzed, petrified, and poisoned. The ice creature obeys only its creator’s commands. The ice object or creature appears in an unoccupied space within 60 feet of you. It melts into a pool of normal water after 24 hours or when it drops to 0 hit points. In extreme heat, it loses 5 (1d10) hit points per minute as it melts. Use the guidelines in chapter 8 of the Dungeon Master’s Guide to determine the hit points of an inanimate object if they become necessary.

Other Properties. Winter's Heart is rumored to possess other properties that can be activated only by an evil being. Frost Giants have long believed that the bearer can freeze entire worlds, while a djinni in the service of a Calishite pasha once claimed that it could be summon and control white dragons, as well as a mighty ice primordial named Cryonax.