Ancestral Shadow Blade

This item appears to be a longsword hilt. While grasping the hilt, you can use a Bonus Action to cause a blade of radiant void 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 shortswords or longswords, you are proficient with the Ancestral Suhadow Blade.

You gain a +2 bonus to attack and damage rolls made with this weapon, which deals 1d6 Necrotic damage in addition to normal longsword slashing damage. When you hit a fey with it, that target takes an extra 1d6 Necrotic damage.

The sword's ominous blade dims all non-magical light in a 15-foot radius (Full becomes dim, dim become dark).  While the blade persists, you can use an action to expand or reduce its radius by 5 feet each, to a maximum of 30 feet each or a minimum of 10 feet each. 

Defensive Instinct

When attuned to the Ancestral Shadow Blade, you can use your reaction to deflect or redirect attacks with ammunittion when you are hit by a ranged weapon attack. When you do so, the damage you take from the attack is reduced by 1d8 + your Dexterity modifier + your level.  If you reduce the damage to 0, it is redirected at the attacker and does damage equal to your Dexterity modifier. The refected missile counts as a magic weapon for the attack and has a range of up to 60 feet.

Curse: If wielding this sword unattuned, this magic longsword has the heavy property and is no longer versatile 

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

Notes: Bonus: Magic, Damage: Necrotic, Replace Damage Type: Necrotic, Weapon Property: Finesse, Ranged Weapon Attack: Piercing, Victory over the previous wielder in combat or be cursed., Damage, Combat, Versatile, Sap