Touched by the Protector of the Civilization

You've been touched by someone who has sworn to protect cities. And even though this creature couldn't give you the ability to use those who are living to help you, now you can channel the power of those who died trying to protect the city and its people. 

Knowledge of the fallen inventors. You gain proficiency with Firearms. If you already have this proficiency, you gain proficiency with one set of tools of your choice

Spectral Strike. You gain the ability to infuse your weapon strikes with the energy borrowed from the deceased citizens of your city. When you hit a creature with a weapon attack, you can cause the attack to deal an extra 2d8 cold or necrotic damage (your choice) to the target.
You can use this ability a number of times equal to your level and regain all expended uses when you finish a long rest.

Phantom Protector. When you see a creature (including yourself) hit by an attack or targeted by a spell, you can use your reaction to summon an invisible barrier of ghostly force that protects the target. Until the start of the target's next turn, the target has a +5 bonus to its AC. 
You can use this reaction a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.