This character must professionally wear two roles, they are not only a champion in service to a benefactor, but they also maintain a certain skill set as a specialized professional.  As an envoy you were not hired just because you know how to use a blade, you were hired because you have a reputation as the best at what you do.

You have a status to maintain and an obligation to your benefactor based on why they hired you.  If you were hired to be a bodyguard, as an envoy you received that job because of your reputation as a professional.  If you were hired to represent your benefactor at the trade market, you are his envoy for the same reasons.  In short, it is not just who you are, but your skills and reputation that have earned you this title.

Professional Skill Set

3rd level Professional Envoy feature

  You are not just a hired blade but an expert in your field. Your benefactor hired you because they need more than just a hired thug, they need a skilled professional. You will attain a free proficiency from your choice of animal handling, history, insight, investigation, or persuasion. You will also be allowed to increase one skill you are proficient to expert level.

Animal Handling

  You have chosen animal handling as a bonus proficiency.

History

  You have chosen history as a bonus proficiency.

Insight

  You have chosen insight as a bonus proficiency.

Investigation

  You have chosen investigation as a bonus proficiency.

Persuasion

  You have chosen persuasion as a bonus proficiency.

Professional Defender

3rd level Professional Envoy feature

  Protective instincts are second nature to you. You receive your choice of either Protection or Interception as a bonus fighter fighting style. Part of your job as a Professional Envoy is to react as a bodyguard to your benefactor.

Interception

  When a creature you can see hits a target, other than you, within 5 feet of you with an attack, you can use your reaction to reduce the damage the target takes by 1d10 + your proficiency bonus (to a minimum of 0 damage). You must be wielding a shield or a simple or martial weapon to use this reaction.

Protection

  When a creature you can see attacks a target other than you that is within 5 feet of you, you can use your reaction to impose disadvantage on the attack roll. You must be wielding a shield.

Tactical Focus

7th level Professional Envoy feature

  You will add your intelligence modifier (minimum of 0) to your initiative rolls as your mental clarity will focus your reactions. Additionally, any round you use your Protection or Interception fighting style to defend another, you will gain advantage on your next attack vs the attacker you were defending against. If you are successful with this strike you will also cause additional weapon damage equal to half your level (rounded down.)  You must make this advantage attack at that opponent before the end of your next turn, or the opportunity will expire.

Skill Mastery

10th level Professional Envoy feature

  You will be allowed to increase another skill you are proficient to expert level. Also, whenever you roll a skill check with a skill you are an expert, you can reroll a result of 7 or less. When you do this, you must accept the second dice result.

Passion of Duty

15th level Professional Envoy feature

  Your passion and sense of duty will grant you advantage to all your intelligence and charisma saving throws so long as you can see the source of the incoming attack. If the attack is from an opponent you cannot see due to a blind-angle, invisibility, heavy concealment, or the use of subtitle spell casting, this advantage does not apply.

Enemy Focus

18th level Professional Envoy feature

  After you roll initiative, you may (as a bonus action) choose a primary enemy during that battle. If you are not incapacitated and that enemy is still standing, you will gain several advantages against that opponent:

• You will result in a critical hit with a roll of 19 or 20,
• Each round your first attack against them will be at advantage,
• You will add your intelligence modifier (minimum of 0) to your armor class against their incoming attacks by mirroring their attack pattern.

You may only choose one enemy per battle. Your Initiative roll will determine when a new battle has begun. If for some reason you have chosen your primary opponent and become incapacitated, your bonuses against that opponent will be lost even if you regain your full fighting strength during that same battle. Likewise, your bonuses against that opponent are lost if they go down, even if they are risen back up again.