Stabbomancer

Stabbomancers are expert assassins, able to become one with the shadows and sneak about unseen. They can sense the life force of others and cut away at it dealing them massive damage.

Dirty Fighting

When you take this sub class at level 3 you learn to become one with the shadows and see other people's life force and how to cut into it dealing massive amounts of damage.

If you attack with advantage because that creature could not see you, you deal an additional 1d6 damage.

This amount increases to 2d6 at level 9 and 3d6 at level 17.

Swift Death

You have learned to move swiftly and efficiently in darkness.

Starting at level 3 while you are in dim light or darkness you may use a bonus action to cast Zephyr Strike on yourself.

You can only use this feature once and must finish a long rest to use it again.

From the Shadows

Starting at 9th level, you can become one with the shadows and move among them.

You may use a bonus action while in dim light or darkness to become invisible till the start of your next turn. Attacking or forcing another creature to make a saving throw ends the effect.

While invisible, you may pass through creatures and objects as if they were difficult turrain but if you end your turn inside a creature or object you are shunted to the nearest unoccupied space and take 1d10 force damage.

You can only use this feature twice and must finish a long rest to regain all uses.

Ghost Blade

Starting at level 9, you can create a shadowy duplicate of your weapon to attack your enemies.

As a bonus action you cast Spiritual weapon but it looks like a shadowy blade. You may use either your Dexterity or Charisma for determining the attack and damage rolls. You can apply your sneak attack to your spiritual weapon as long as that weapon has advantage or if another enemy of the target is within 5 feet of it, that enemy isn't incapacitated, and you don't have disadvantage on the attack roll.

You can only cast this spell in this way once and must finish a long rest to use this again.

A Thousand Cuts

Starting at level 13 you can take a portion of an enemy's life force and use it as an attack against another creature.

When your melee attack crits or your melee attack reduces a creature to zero hit points, you may make an additional attack against another creature within melee range as part of your attack action, this attack looks like a shadowy blade shoots out of you.

If the triggering attack had sneak attack then the shadow attack deals an additional 2d6.

Shadow Step

Starting at level 17 you gain the ability to turn into shadow and in a split second dart around the battlefield attacking multiple enemies.

As an Action, you may cast steel wind strike using either your Dexterity or Charisma to calculate your melee spell attack and you do not get sneak attack on any of these attacks but you may choose one of those attacks before you roll to attack, that attack can crit on a 19 - 20.

You can only activate this ability once and must finish a long rest to use it again.

Executioner's Blade

Starting at 17th level, you can create an evolved form of your Ghost Blade.

As a bonus Action you may cast spiritual weapon at level 4. You may use either your Dexterity or Charisma for calculating attack and damage. You can apply your sneak attack to your spiritual weapon as long as that weapon has advantage or if another enemy of the target is within 5 feet of it, that enemy isn't incapacitated, and you don't have disadvantage on the attack roll. 

You can only use this feature once and you must finish a long rest before you can use it again.