This is a charged attack, costing no additional Action Points but 10 Morality when compared to an uncharged attack. An attack charged by Wrathful Smite deals +10 damage and damage type is changed to Holy.
Each time this attack is used, there is a 25% chance that the character's infernal nature gets the better of them. In this case, the morality cost is 15 morality, the attack deals +20 damage, and the damage type is changed to Unholy instead.
Note: The health and morality penalty for using an attack not matching your characters alignment is ignored when dealing unholy damage with this skill.