Alondite & Ragnell (5e Equipment)
From D&D Wiki
Weapon (greatsword), artifact (requires attunement)
These sister blades are national treasures of the Begnion Empire, once wielded by the beorc hero Altina. They were blessed by the Goddess of Order, Ashera, which granted them immense power and rendered them invulnerable. In addition to their sheer power, they can be used to sling powerful shockwaves to attack from afar.
Both of these blades are currently in the possession of the Black Knight. He wields Alondite as his favored weapon, and seeks to grant Ragnell to an opponent worthy of facing him in a duel.
You gain a +3 bonus to attack and damage rolls made with one of these weapons. While wielding one of them, your Armor Class also increases by 2, and you can choose to use your Strength or Dexterity modifier for attack and damage rolls. They are immune to effects that corrode or damage metal and are utterly indestructible.
When you make an attack with one of these weapons, you can choose to make a ranged spell attack with the blade, creating a powerful shockwave, instead of making a conventional melee attack. This spell attack has a range of 15 feet, and has the same attack bonus and deals the same damage as a melee attack with the blade.