Wondrous Item (mask/helmet) , Legendary (unique/requires attunement)
This mask/helmet of shining gold has swept-back eagle wings and a beak shaped nose guard. The mask reshapes to fit the face and head of a wearer attuned to it. While you are wearing the mask and attuned to it, you gain the following benefits.
Damage Absorption. You have resistance against necrotic and fire damage. If you already have resistance to the damage from another source, you instead have immunity to it. If you already have immunity to the damage from another source, whenever you are subjected to it, you take none of that damage and regain a number of hit points equal to half the damage dealt.
Combat Foresight. While you are wearing no armor, you can add your Wisdom bonus to your Armor Class.
Strength of the Ancients. 3 times per long rest, you can supernatural strength, as if under the effects of a Potion of Fire Giant Strength.
Sunbeam. A beam of sunlight equivalent to a Sunbeam spell flashes out from the eyes of the mask. This ability has a recharge of 6.
Eyes of the Sun. You gain darkvision out to 60 feet, or to an additional 60 feet if you already have that sense. Once per day, you can gain blindsight out to 30 feet for 5 minutes.
Celestial Tongue. You can speak and understand Celestial.
Legendary Resistance (1/Day). If you fail a saving throw, you can choose to succeed instead.