Shadow Dragon Armor (5e Equipment)
From D&D Wiki
While wearing this armor, you gain a +2 bonus to AC, you have advantage on saving throws against the Frightful Presence and breath weapons of dragons, and you have resistance to necrotic and one damage type that is determined by the kind of shadow dragon it is made from.
Living Shadow. While in dim light or darkness, you have resistance to nonmagical bludgeoning, piercing, and slashing damage.