Moonsteel Rapier

The blade of this magic weapon seems to shine from within with a pale white light. The weapon deals an extra 1d6 radiant damage to any creature it hits. If the creature is not in its true form, it becomes frightened until the start of your next turn. At the start of its turn, a creature frightened in this way must succeed on a DC 13 Charisma saving throw or immediately return to its true form.

Finesse: When making an attack with a finesse weapon, you use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.

Proficiency: martial, rapier Source: Book of Ebon Tides p. 210 (Third Party), Player's Handbook (2014) p. 149