Avenging Sun Blade

A Sun Blade that has been enchanted with the Holy Avenger Properties. 

You gain a +3 bonus to Attack and Damage Rolls made with this weapon, which deals radiant damage instead of slashing damage. When you hit an Undead with it, that target takes an extra 1d8 radiant damage.

When you hit a fiend or an Undead with it, that creature takes an extra 2d10 radiant damage.

While you hold the drawn sword, it creates an aura in a 10-foot radius around you. You and all Creatures friendly to you in the aura have advantage on Saving Throws against Spells and other Magical Effects. If you have 17 or more levels in the Paladin class, the radius of the aura increases to 30 feet.

The sword's luminous blade emits bright light in a 15-foot radius and dim light for an additional 15 feet. The light is sunlight. While the blade persists, you can use an Action to expand or reduce its radius of bright and dim light by 5 feet each, to a maximum of 30 feet each or a minimum of 10 feet each.

Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Radiant, Bonus: Melee Weapon Attacks, Proficiency: Longsword, Damage: Radiant, Damage: Acid, Versatile, Sap