Acuity (Rune)

This rune is written in Infernal and can be transferred to any weapon.

The creature who transfers this rune to a weapon chooses either Intelligence, Wisdom, or Charisma.  When you make an attack with the weapon, you can use the chosen ability, instead of Strength or Dexterity, for the attack and damage rolls.

Curse.  When you score a critical hit with the weapon, you take psychic damage equal to the ability modifier you used for the attack.