Blade of Night

One wonders what the bumps in the night be, but you know it is the sounds of enemies running for their lives. Blessed by the Night Mother you have learned to harness the power of shadow to aid you in all of your endeavors. 

Bonus Proficiencies

When you choose this archetype at 3rd level, you gain proficiency with the poisoner’s kit, and the Stealth skill. Your proficiency bonus is doubled for any ability check you make that uses either of those proficiencies.

Shadow Strike

Starting at 3rd level, you are at your deadliest when you attack from the shadows. You have advantage on attack rolls against any creature when you attack from darkness or from shadows. In addition, the first time you hit a creature in this way each combat is a critical hit (Once per Combat).

Mark of the Night

Starting at 9th level, you can cast the spell Darkness once per day. You are not affected by this spell and it only lasts for 30 seconds, until dispelled, or until concentration is lost.

You also gain Darkvision of 60ft. If you already have Darkvision you range is increased by 30ft.

Friend of Shadow

At 13th level, you gain advantage on all stealth checks while you are trying to hide in shadows or during the night. This advantage is in addition to any other effects that would giv you advantage on stealth.

Additionally, while you are in darkness, you may use your cunning action to make an attack roll.

You treat dim light as darkness for this feature.

Master of Darkness

Starting at 17th level, you become a master of attacking from the shadows. When you attack and hit a creature from shadow, it must make a Strength saving throw (DC 8 + your Dexterity modifier + your proficiency bonus). On a failed save, double the damage of your attack against the creature. (Once Per Combat)