Lethal Observer

You are a two-fold being. One very capable of being able to kill, but one who knows how to collect information from up close and afar. Your art is that of subterfuge, of being unseen even when close to your target. Of being able to find out the details that many often overlook. You have an eye for traps, insights for lies, and an eye for deception and detail that few others can match. 

This subclass is a fusion of the Inquisitive Archetype and the Assassin. An attempt to fuse the better elements of both while giving up elements of the other.

Bonus Proficiences

When you choose this archetype at 3rd level, you gain proficiency with the disguise kit and one tool of your choice (typically poisoner's kit or alchemist kit).

 

Ear for Deceit

When you choose this archetype at 3rd level, you develop a talent for picking out lies. Whenever you make a Wisdom (Insight) check to determine whether a creature is lying, treat a roll of 7 or lower on the d20 as an 8.

Eye for Detail

Starting at 3rd level, you can use a bonus action to make a Wisdom (Perception) check to spot a hidden creature or object or to make an Intelligence (Investigation) check to uncover or decipher clues.

Insightful Fighting

At 3rd level, you gain the ability to decipher an opponent’s tactics and develop a counter to them. As a bonus action, you can make a Wisdom (Insight) check against a creature you can see that isn’t incapacitated, contested by the target’s Charisma (Deception) check. If you succeed, you can use your Sneak Attack against that target even if you don’t have advantage on the attack roll, but not if you have disadvantage on it.

This benefit lasts for 1 minute or until you successfully use this feature against a different target.

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.

Unerring Eye

Beginning at 13th level, your senses are almost impossible to foil. As an action, you sense the presence of illusions, shapechangers not in their original form, and other magic designed to deceive the senses within 30 feet of you, provided you aren’t blinded or deafened. You sense that an effect is attempting to trick you, but you gain no insight into what is hidden or into its true nature.

You can use this feature a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses of it when you finish a long rest.

Deadly Precision

At 17th level, you learn to exploit a creature’s weaknesses by carefully studying its tactics and movement. While your Insightful Fighting feature applies to a creature, your Sneak Attack damage against that creature increases by 3d6. Against a surprised target, your Sneak Attack damage doubles to 6d6, for maximum lethality.