Weapon (any sword)

When you attack a creature with this magic weapon and roll a 20 on the attack roll, that target takes an extra 3d6 necrotic damage, provided that the target isn’t a construct or an undead. You gain temporary hit points equal to the extra damage dealt.

Magical Effects

• When Activated: Adds 3d6 necrotic damage to base damage. Condition: if the target isn’t a construct or an undead