Storm's Roar Shield (Patreon)

Armor (shield), very rare (requires attunement)

This round shield is originally of storm giant make. While holding it, you have resistance to lightning damage and a +1 bonus to AC. This bonus is in addition to the shield’s normal bonus to AC.

Storm Strike. While holding the shield, you can use your reaction when you take lightning or thunder damage to charge a melee weapon you're holding with that energy. The next time you hit a target with that weapon before the end of your next turn, the target takes an extra 2d8 damage of the charged type.

Storm's Reverie. You can use an action while holding the shield to create a whirling storm around you. Other creatures within 15 feet of you must make a DC 16 Constitution saving throw; if a creature is within 5 feet of you, you can choose to exclude it from this effect. On a failed save, a creature takes 3d8 lightning damage and 3d8 thunder damage and is deafened and unable to make opportunity attacks until the end of your next turn. On a successful save, a creature takes half as much damage and isn't deafened or unable to make opportunity attacks. Regardless, using this effect also activates the shield's Storm Strike property (no action required): a target hit with the charged weapon takes both 2d8 lightning damage and 2d8 thunder damage, instead of one or the other. This property can't be used again until the next dawn.

The giants' bellows were bested only by the roar of the storm above them. Together, they sang a song of unbridled power. In their wake, only ruin.