Unerring Deliveries

At the start of dawn you obtain two kind letters one is Diplomat’s Letter and the other is Letter of Termination.
When combat starts you gain a number of Diplomat’s Letters equal to your proficiency bonus. You may immediately or as an action attempt deliver them to any number of creatures. (Acceptance of the letter means you lose the letter)

Each creature may choose to accept the letter. If they accept your letter they Recieve the Diplomat’s Letter.
Diplomat’s Letter. When you gift this letter the creature is unable to take any action to harm or cause you to have a detrimental condition until the end of combat or when you cause harm to them. While they have the letter they have a +2 bonus to their Armor Class and may use a reaction to make a weapon attack against a creature you hit with a critical hit.
If they refuse the letter you may attempt to deliver a Letter of Termination against that creature.
Letter of Termination. You may attempt to gift them this letter as a bonus action. Choose AC, Saves, or Attack Rolls. They may take the letter. If they do they have penalty equal to their wisdom modifier to the choice until the end of combat. If they refuse you may have them take 10d6 psychic damage times the number of attempts you have made against them.

Once a creature has accepted a letter you cannot attempt to deliver a letter until the next combat