The mantle has 3 charges, and regains 1d3 expended charges when you complete a long rest. An attuned wearer can use their action and expend 1 of its charges to exhale a blast of freezing wind in a 15-foot cone.

Each creature in that area must make a Dexterity saving throw (DC = 8 + wearer's proficiency bonus + wearer's Constitution modifier), suffering 4d8 cold damage on a failed save, or half as much damage on a successful one.

The wearer can spend extra charges when they use this feature, increasing the size of the cone by 15 feet for each additional charge spent.