You focus your training in the art of surprise. You arrive in cover as quickly as you had left it (or maybe you never left it at all), disorienting and confusing foes, leaving them clueless as to who, or what, sent them to their death. Spies, contract killers and other schemers, even those who prefer the joy of confusing and tricking their foes, may favor this archetype.

Lurker

When you choose this archetype at 3rd level, you learn how to strike enemies while ducking to and from cover. During your turn, if you make a melee attack against a creature, that creature can't make opportunity attacks against you for the rest of your turn. In addition, if you land a strike on a creature while coming out of stealth, your speed increases by 15 feet till the end of your turn, allowing you to slip past your foes with ease.

Tactical Strike

At 3rd level, you gain one of the following features of your choice.

Follow Up

You know when a creature is at its most vulnerable, and will ensure that the opportunity is not missed. After landing an attack against a creature with advantage, you can make an additional attack against the same enemy as a bonus action, adding half the amount of sneak attack dice you have (rounded down) to the damage.

Height Advantage

If the creature you are targeting with an attack is of a size larger than you, you can aim your shot at their legs in order to take them down a peg. The creature must make a Constitution saving throw (DC 8 + your Dexterity modifier + your proficiency bonus) or fall onto their knees prone. The targeted creature cannot be levitating and must have some feature of it's being on the ground for this to work, and creatures more than 2 sizes larger than you have advantage on the save.

Sniper

The shadows have come to be your greatest ally, you know their benefits well. When you are hidden from a creature and make a weapon attack, your position is no longer revealed. Instead your Stealth score takes a -2 penalty for each attack made, stacking with each attempt. Once your Stealth score matches the passive perception of one of your enemies, your position is then found and your Stealth then fails. This penalty resets once you reposition yourself to a new hiding spot.

Slippery

Beginning at 9th level, whenever you take the disengage action, or after making a melee attack, you can freely move through any other creature's space without becoming impeded. In addition, you have advantage on saving throws against effects that would grapple or restrain you.

Blurred Movement

Starting at 13th level, you have advantage on a Dexterity (Stealth) check if you move more than half your speed on the same turn, confusing your foes with your lightning fast repositioning or your erratic evading.

Trained Strike

At 17th level, you gain the ability to put all of your focus into a single moment, as you set up the perfect opportunity to strike. Once per combat, when you make a weapon attack against a creature, you can expend your reaction to ensure the attack is a crucial one, making the attack a critical hit.