Flirting with death

Having lived a life filled with killing, you're practically bedfellows with death itself. You can seize another's fear of death to your advantage, and stare down the pale horseman unflinchingly. 

You are immune to being frightened, and can frighten those immune to it, but can't do this at advantage. 

When you strike a frightened target, deal a large amount of extra damage and gain Temporary Hit points for your troubles. 

Furthermore, your lethal movements with weapons have translated well to your magic, allowing you to add your dexterity modifier to your spell attacks, and your frightening aura allows you to add your Charisma modifier to your Dexterity weapon attacks.