Arcane Blade

This item appears to be a longsword hilt. While grasping the hilt, you can use a bonus action to cause a blade of pure arcane or elemental energy to spring into existence, or make the blade disappear. While the blade exists, this magic longsword has the finesse property. If you are proficient with short swords or longswords, you are proficient with the arcane blade.

You gain a +2 bonus to attack and damage rolls made with this weapon. As a bonus action you may switch the damage type that this weapon deals to one of the following: cold, fire, force, lightning, necrotic, psychic, or radiant damage instead of slashing damage. The weapon deals your chosen type until you use this feature to pick another one. When an attack with this weapon hits a target, it deals 1d8 additional damage. When you hit an undead with it while the damage type is radiant, that target takes an extra 1d8 radiant damage.

The sword's luminous blade emits bright light in a 15-foot radius and dim light for an additional 15 feet. The light is magical. 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: Force, Damage: Force, Replace Damage Type: Force, Bonus: Melee Attacks, Weapon Property: Finesse, Versatile, Sap