Veilpiercer, Kunai of the Ashen Veil

Forged by the master weapon-smiths of the Ashen Veil, this dagger channels the wielder’s soul into countless mirrored projections, blades of pure elemental essence that strike, pierce, and linger before returning through the unseen veil. The true dagger never leaves the wielder’s hand; all “throws” are echoes of intent, reflections cast from the weapon’s spirit.

You have a +3 bonus to attack and damage rolls made with this magic weapon.

Thrown attacks made with this weapon deals 2d4 damage instead of 1d4. The weapon otherwise functions as a normal dagger.

When you make thrown weapon attacks with this weapon your range doubles to (40ft/120ft). Instead of throwing the physical blade, you create a spectral projection of it. Whenever you hit a creature with a thrown attack using this weapon, the strike leaves behind an embedded spectral dagger of your chosen elemental type. These projections remain lodged within the target until they are recalled or dismissed. You can dismiss the spectral daggers embedded in one creature of your choice as a free action on your turn.

You can choose to attune to this weapon. While attuned, you gain the following benefit:
Elemental Armament.
The dagger deals an additional 2d8 damage of a type of your choice: acid, cold, fire, force, lightning, necrotic, poison, psychic, radiant, or thunder. You choose the damage type when you finish a long rest, and you can change it whenever you finish another long rest.

As a bonus action, you can prematurely change the dagger's elemental damage type to another option from the list above.

Ashen Bloom.
When you take the Attack action, you can choose to unleash a storm of elemental daggers instead of making your normal attacks.
You choose to either throw your dagger's in a a 40-foot cone originating from you, or a 20-foot sphere centered on you.

Each creature within the chosen area must make a Dexterity saving throw (DC = 8 + your attack modifier with this dagger). On a failed save, you make two thrown weapon attacks against that creature. On a successful save, you make one thrown weapon attack against that creature. These attacks automatically hit and are treated as thrown weapon attacks made with this dagger. 

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

Return to the Veil.
As a bonus action, you can recall all spectral daggers you have created, from normal attacks, or Ashen Bloom. When you do, each creature that has one or more embedded daggers takes 2d8 damage of the weapon’s current elemental type for each dagger embedded within it. The projections slice back through their targets in a flash before dissipating into motes of light and reforming around your hand. After the recall, the residual energy empowers your next strike. The next time you hit with this weapon before the end of your next turn, that attack deals an additional 2d6 damage of the weapon’s current elemental type for each dagger recalled using this feature.

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

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

Notes: Bonus: Magic, Damage: Acid, Damage: Thrown Weapon Attacks, Damage, Combat, Finesse, Light, Thrown, Nick