Hired killers exist in every era of human history, every culture, every time. Assassins are the modern incarnation of that brotherhood of storied murderers, outlaws focused on infiltration, disguise, and the subtle arts of end lives as quickly and quietly as possible. Every corporation has their own stable of assassins, preferring to remove potential adversaries without fuss rather than engaging in open combat whenever possible. Rogue assassins are some of the most feared people in the freelancing world, often turning their deadly skills against their former masters.
Bonus Proficiencies
When you choose this archetype at 3rd level, you gain proficiency with disguise kits and poison kits.
Assassinate
Starting at 3rd level, you are at your deadliest when you get the drop on your enemies. You have advantage on attack rolls against any creature that hasn't taken a turn in the combat yet. In addition, any hit you score against a creature that is surprised is a critical hit.
Infiltration Expertise
Starting at 9th level, you can unfailingly create false identities for yourself. You must spend seven days and $$2500 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, identicards, and official-looking certification to establish yourself as a member of a corp from a distant city so you can insinuate yourself into the company of other executives.
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.
Impostor
At 13th level, you 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 mannerisms.
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.
Death Strike
Starting at 17th level, you become a master of instant death. When you attack and hit a creature that is surprised, 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.