A sword hilt made from crystallised shadow, harvested and shaped on the Shadowfell, it apparently lacks a physical blade. Only  those with a deep connection to the plane of shadows can wield this weapon safely, anyone else feels nothing but complete immobilizing despair

In its base form, this can barely be called a weapon, being simply a conduit between the creator and the wielder.

While you are attuned to Wraithblade, you gain the following benefits.

You have a +1 bonus to attack and damage rolls made with Wraithblade

You have darkvision out to a range of 30 feet. If you already have darkvision, Wraithblade increases its range by 30 feet.

Blood Price.

You can use your action to activate any of the features of this item. The first time after a Long Rest that you activate each feature you must expend a hit dice, when you do you must roll your hit dice and reduce your hit points by the number rolled plus your proficiency modifier. Any hit dice expended this way cannot be expended on a Short Rest, but they are recovered after a Long Rest. Any time you use your action to activate a feature of this item after expending a hit dice, before your next Long Rest, you only need to reduce your hit points by an amount equal to your proficiency modifier.

Blade of Blood and Shadow.

When you activate this feature, darkness and shadow burst forth from the hilt to form a black blade about a foot in length. This blade appears to become mist in bright light but becomes visibly solid in total darkness. The blade lasts for 4 hours after which it dissipates, like a drop of ink in a pond. This blade leaves no wound on living flesh, as it damages its targets soul.

When you hit with an attack using Wraithblade and your target is in bright light, this weapons damage die is 1d4.

When you hit with an attack using Wraithblade and your target is in dim light, this weapons damage die is 2d4.

When you hit with an attack using Wraithblade and your target is in darkness, this weapons damage die is 3d4.

Any damage done by this feature is psychic damage.

Torrent of Darkness.

When you activate this feature, thick inky shadows pour forth from the weapon and create a 20-foot radius sphere of magical darkness.

This magical darkness is centred on Wraithblade and moves with it.

Whilst in this darkness creatures other than the you have Disadvantage on Wisdom and Charisma Saving Throws.

You can see in this darkness as if it were non-magical darkness, but cannot see beyond the edge of the sphere.

This effect lasts for 1 minute, or until you cancel it (no action required).

Dark Servants.

When you activate this feature, shadows bleed from the blade, take on a form similar to yours and move through and around you, mimicking your movements. you gain the benefits of the spell Mirror Image.

While you under the effect of this feature, and you are in darkness you gain a bonus to your AC equal to the amount of mirror images that remain.

While you under the effect of this feature, and you are in darkness, if you hit a creature using Wraithblade the phantom images of you also attack, doing Psychic damage equal to your Wisdom modifier for each mirror image which remains

Dispelling Effects.

The effects created by the features of this item are susceptible to dispelling and counter-spelling, the features count as spells cast at 7th level for this purpose.

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

Notes: Sense: Darkvision, Damage: Necrotic, Damage: Necrotic, Disadvantage: Wisdom Saving Throws, Bonus: Magic, Ignore Weapon Property: Thrown, Disadvantage: Charisma Saving Throws, being who has a deep connection to the shadowfell., Damage, Control, Buff, Finesse, Light, Thrown, Nick