Infiltrator

You train yourself to be a master of subterfuge and sabotage. With infiltrator kits, this archetype allows you to carry a vast array of tools and gadgets to stalk, impair and kill enemies undetected.  As you train in stealth and agility, you also upgrade your bombs and poisons to give you a strong advantage on the battlefield.

Coup de Grace

At 3rd level, you gain the ability exploit an enemy's vulnerability. Once per long rest, when you hit a target with an attack that is under any negative condition, you can choose to make it a critical hit.

Hooked Up

At 3rd level, you gain proficiency to equip the Infiltrator Kit I. This kit is upgraded at level 9 and 17. 

Because of your kit, you have the tools and skills to scale vertical surfaces, gaining the ability to climb faster than normal; climbing no longer costs you extra movement.

(Note: you must find and add these kits as well as their contents to your Homebrew collection: Infiltrator Kit I, Infiltrator Kit II, Infiltrator Kit III)

Pick your Poison

At 3rd level, the way of the Infiltrator has taught you exotic new techniques for making poisons with higher potency. You gain proficiency with the poisoner's kit. During a short rest, you can add your proficiency modifier to the DC of any poison you craft, purchase or harvest.

Eyes on the Prize

Starting at 9th level, you have advantage on any Wisdom (Perception) or Intelligence (Investigation) skill check if a target or object is observed for at least 1 minute. Additionally, you know the approximate value of the observed object.

Where it Hurts

By 13th level, you can spot enemies when they are at their most vulnerable moment. When you hit with an bomb or trap, against a target with full health, they have disadvantage on saving throws against the device.

Quick and Dirty

When you reach 17th level, you have become a master at springing ambushes. You have advantage on initiative rolls and one extra charge of Coup de Grace per long rest.