Violet Assassin

You focus your training on the grim art of death. Those who adhere to this archetype are diverse—hired killers, spies, bounty hunters, and even specially anointed priests trained to exterminate the enemies of their deity. Stealth, poison, and disguise help you eliminate your foes with deadly efficiency.

Bonus Proficiencies

When you choose this archetype at 3rd level, you gain proficiency with the disguise kit and the poisoner’s kit.

Assassinate

Starting at 3rd level, you are at your deadliest when you get the drop on an enemy. You have advantage on attack rolls against creatures that haven’t acted yet in initiative and when you attack and hit a creature that is surprised or you roll a 20 on the die against them, it must make a constitution saving throw (DC 8 + your Dexterity modifier + your proficiency bonus). On a failed save, double the damage of your attack against the creature.
When you use this feature outside of surprise, you can only do so a number of times equal to your proficiency bonus per long rest.

Infiltration Expertise and Anything is A Weapon

Infiltration Expertise:
Starting at 9th level, you can unfailingly create false identities for yourself. You must spend seven days and 25 gp to establish the history, profession, and affiliations for an identity. You can't establish an identity that belongs to someone else. For example, you might acquire appropriate clothing, letters of introduction, and official-looking certification to establish yourself as a member of a trading house from a remote city so you can insinuate yourself into the company of other wealthy merchants.

Thereafter, if you adopt the new identity as a disguise, other creatures believe you to be that person until given an obvious reason not to and at 13th level in this class, you also gain the ability to unerringly mimic another person's speech, writing, and behavior. You must spend at least three hours studying these three components of the person's behavior, listening to speech, examining handwriting, and observing mannerism.

Your ruse is indiscernible to the casual observer. If a wary creature suspects something is amiss, you have advantage on any Charisma (Deception) check you make to avoid detection.

Anything is A Weapon:
Starting at 9th level you've trained in being able to turn even the most mundane of tools into a deadly weapon. You gain proficiency in improvised weapons and you may use sneak attack with them, improvised weapons gain the finesse property provided you can use it with one hand.

Marked Target

At 13th level, you can choose to mark a creature you can see within 60ft as a bonus action giving you a brief insight into their weaknesses, until the end of your turn you have advantage on the first weapon attack you make against the target and you may trigger sneak attack against them even if you don’t have advantage or an ally within 5ft. All other sneak attack rules still apply.
You can use this ability a number of times equal to your proficiency bonus, and you regain all uses when you finish a short or long rest.

Death Strike

Starting at 17th level, you become a master of instant death. When you attack and hit a creature that is surprised, the attack is considered a critical hit as you know exactly where to strike for maximum effectiveness.
In addition, a creature that takes your sneak attack damage, you can cause them to start bleeding for half your sneak attack dice rounded down at the start of each of its turns. At the end of the creature’s turn it may make a Constitution saving throw (DC 8 + your Dexterity modifier + your proficiency bonus) to staunch the bleeding, ending the effect on a success. You can use this feature a number of times equal to your proficiency bonus and you regain all uses at the end of a long rest.