You excel at getting the drop on your enemies and striking them before they strike you.

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.

Bonus Tool Proficiencies

When you choose this archetype at 3rd level, you gain proficiency with the poisoner's kit and the disguise kit or a different tool set.

Rakish Audacity

Starting at 3rd level, your confidence propels you into battle. You can give yourself a bonus to your initiative rolls equal to your Charisma modifier.

You also gain an additional way to use your Sneak Attack; you don't need advantage on the attack roll to use your Sneak Attack against a creature if you are within 5 feet of it, no other creatures are within 5 feet of you, and you don't have disadvantage on the attack roll. All the other rules for Sneak Attack still apply to you.

Ambush Master

Starting at 13th level, you excel at leading ambushes and acting first in a fight.

You have advantage on initiative rolls. In addition, the first creature you hit during the first round of a combat becomes easier for you and others to strike; attack rolls against that target have advantage until the start of your next turn.

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.