Mjölnir

Forged by the dwarf brothers Brokkr and Sindri, this hammer is said to be capable of leveling mountains. You gain a +4 bonus to attack and damage rolls made with this warhammer. If you are not wearing the belt Megingjörð and the iron gloves Járngreipr , you have disadvantage on attack rolls using Mjölnir.

Giant’s Bane. When you roll a 20 on an attack roll made with this warhammer against a giant, the giant makes a DC 17 Constitution saving throw or dies. In addition, when making a weapon attack using Mjölnir against a giant, you may treat the giant as if its type were fiend or undead.

Hurl Hammer. The warhammer has 5 charges. While attuned to it, you can expend 1 charge and make a ranged weapon attack with the warhammer, hurling it as if it had the thrown property with a normal range of 20 feet and a long range of 60 feet. If the attack hits, the warhammer unleashes a thunderclap audible out to 300 feet. The target and every creature within 30 feet of it makes a DC 17 Constitution saving throw or becomes stunned until the end of your next turn. The warhammer regains 1d4+1 expended charges daily at dawn.

Summon the Storm. While attuned to this warhammer, you can use an action to expend 2 charges and cast call lightning , or you can spend 1 minute swinging the warhammer to expend 5 charges and cast control weather .

Titanic Blows. While attuned to this warhammer, its weapon damage increases to 2d6.