Dragonmail

Armor (medium), legendary (requires attunement)

This +2 scale mail is crafted from the hide of an ancient dragon.

While wearing this armor, dragons have disadvantage on attack rolls against hitting you and you have resistance against their attack.

You also have resistance to damage against the damage type determined by the damage dealt by the breath weapon of the dragon from whose hide it was made. This resistance protects against damage from such attacks, but not any other negative conditions which may come from them.

Epic Attunement. You gain immunity rather than resistance to the type of damage noted above, but only against the breath weapons and other abilities of dragons.

Furthermore, whenever you would take damage from a dragon’s breath weapon, as a reaction you can halve the damage you take if you fail the saving throw (this stacks with the resistance the armor provides), or take no damage if you succeed the saving throw.