Executioner

Your character has become adept at the grim work of an executioner. You may now kill Unconscious creatures with a single attack as a Bonus Action.

You may also chose to finish them off using an Action, in which case you will perform horrifying feats of violence against the downed  enemy. All creatures who see you do this must make a Wisdom Saving Throw with a DC of 10 + your character's level. On a failure, they are Frightened for a round. Creatures immune to Psychic Damage aren't affected, and those Resistant to it make the Saving Throw at advantage.