Holy Avenger
Weapon,
Legendary
(requires attunement; cost 10000 gp)
Crafting Components
Holy symbol that has traveled to an Upper Plane
You gain a +3 bonus to attack and damage rolls made with this magic sword. While you are attuned to the sword and use it to attack a fiend or undead, on a hit it deals an extra 2d10 radiant damage. In addition, while drawn the sword creates an aura in a 10-foot radius around you. You and friendly creatures in the aura gain advantage on saving throws against spells and other magical effects. If you have 17 or more levels in the herald class, the aura increases to a 30-foot radius.
Source