Frost Domain

Frost Domain clerics worship deities such as Auril and Talos. Their focus on deadly combative magic earns them a negative reputation in many places, but they can be powerful allies.

Bonus Proficiency

When you choose this domain at 1st level, you gain proficiency with heavy armor and warhammers.

Brutal Cold

Whenever you roll a 1 or 2 on a damage die for a spell that deals cold damage, you can reroll that die and must use the new roll.

Channel Divinity: Frozen Tomb

When you hit a creature with a melee attack, you can attempt to freeze it. The creature must succeed on a Strength saving throw against your spell save DC or be encased in ice, becoming restrained and having three-quarters cover against all attacks. When a creature starts it's turn imprisoned in this way, it takes 2d4 cold damage and must succeed on a Constitution saving throw against your spell save DC or gain one level of exhaustion. A creature can repeat the Strength saving throw at the end of each of it's turns, ending the effect on itself on a success. You can use this ability once per short or long rest, and this increases to twice at 6th level and three times at 18th level. The cold damage increases to 4d4 at 5th level, 6d4 at 11th level, and 8d4 at 17th level.

Improved Spellcasting

When you cast a spell that deals cold damage, double your proficiency bonus when calculating save DC. This applies to spells that do not deal exclusively cold damage, such as ice knife

Advanced Spellcasting

With great effort, you can wield magic more powerful than most comparable spellcasters. Choose one of the spells listed below. This spell can be cast using a 4th level spell slot, but will inflict 4d6 psychic damage as backlash. This damage cannot be reduced or ignored in any way. At 14th level, the backlash decreases to 2d6.

Freezing Sphere

You can cast freezing sphere using this feature.

Investiture of Ice

You can cast investiture of ice using this feature.

Wall of Ice

You can cast wall of ice using this feature.

Deadly Cold

Starting at 17th level, your cold spells have become so potent that they weaken the vitality of the target. When a target fails a saving throw against a spell that deals cold damage, their Constitution score is reduced by an amount equal to half the spell's level (rounded down). For example, a target that fails a saving throw against cone of cold would have their Constitution score reduced by 2. Consequently, the target's hitpoint maximum is also recalculated, and they lose hitpoints equal to the reduction in hitpoint maximum. This effect will disappear after a long rest, or can be removed by greater restoration or a similar spell of the same or higher level.