Weapon

Legendary

Calming, Lacerating, Light, Prime, Quiet Relentless
Base Weapon: Scimitar

Complicated Properties

Lacerating. When you deal 6 or slashing damage, the target must succeed on a con save or gain 1 level of exhaustion. DC 10 + 1/2 damage dealt

Prime. You can use any ability score as the modifier for this weapon.

Quiet. This weapon makes no noise when used.

Relentless. You can add your Proficiency Bonus to both attack and damage rolls.

Weapon Art:

Nightmare Veil. You emit a 60-foot-radius cloud of condensed darkness centered on yourself, which lasts for 30 seconds.

While active, your movement speed is doubled and you gain an additional action on each of your turns.

However, you can't cast spells, regain HP, or move beyond the Veil.

If a force would move you outside the veil, you teleport to the center of the veil instead.

Additionally, the Veil counts as magical darkness for Darkvision and lowers the range of true sight by half, but you can see everything inside it as though you had true sight.

Additional rules for Weapon Art's can be found here: Soulcraft Weapons