Morale Crusher

You are a terrifying force to face in combat, striking down anyone who comes near. Whenever you reduce a hostile creature to 0 HP in combat, all hostile creature within 10 feet of you must make a Charisma saving throw (save DC 8 + your Charisma modifier + your proficiency bonus) or be frightened until the end of their next turn. This effect can only be triggered by the player once per round. A creature who saves successfully is immune to this effect until the end of their next turn.