Urnblade

Weapon (scimitar), rare (requires attunement)

This item appears to be a small cremation urn. While grasping the urn, you can use a bonus action to speak its first command word and cause its lid to unseal. When you do, a curved blade of dark smoke pours from the mouth of the urn. Speaking the command word again reseals the urn and causes the blade to disappear. If you are proficient with shortswords or longswords, you are proficient with the urnblade.

You gain a +1 bonus to attack and damage rolls made with this magic weapon, which deals necrotic damage instead of slashing damage.

Shadow Ally. While holding the urn, you can use an action to speak its second command word to animate your body's shadow, transforming it into an undead creature. When you do, your body's shadow detaches from you and becomes a shadow in an unoccupied space that you can see within 10 feet of you.

On your turn, you can mentally command the shadow if you aren't incapacitated. You decide what action the shadow takes and where it moves during its next turn, or you can issue it a general command, such as to attack your enemies or guard a location. The GM has the shadow's statistics. This shadow doesn't cause a new one to appear when a non-evil humanoid dies from its attacks.

The urnblade's bonus to attack and damage rolls becomes +2 while the summoned shadow exists. In addition, if you are the target of an attack and are within 5 feet of the shadow, you can use your reaction to command your shadow to become the target of the attack instead.

The shadow disappears when it drops to 0 hit points, when it's farther than 120 feet from you, or when you use an action to dismiss it. When it disappears, your cast shadow returns. If the shadow drops to 0 hit points, there is a cumulative 5 percent chance that the urn turns to dust and is destroyed.

"I never understood how some creatures could be afraid of their own shadow. Now I do."