Shadowblade

Most rogues who gain this ability are one with the dark, spending most of their time in the shadows, and steering clear of social situations. How did you gain these abilities? What do you use them for? 

Shadow Strike

Starting at 3rd level, you learn how to use the shadows to your advantage in battle. As a bonus action, you can call the darkness to your blade. Your next melee attack deals an extra 1d6 necrotic damage. You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses after a short or long rest.

When you reach certain levels, the damage die increases: at 5th level (d8), 11th level (d10), and 17th level (1d12)

Discreet Teleportation

Starting at 9th level, you have gained the ability to teleport in the darkness. While in dim light, or darkness, you can use an action to teleport 30 feet in any direction to a location you can see. This movement doesn't trigger opportunity attacks.

Shadow Form

Starting at 13th level, you can assume a shadow form. As a bonus action, you can take on a shadow-like appearance for 1 minute. In this form, you can move through solid objects, and creatures as if they were difficult terrain. If you end your turn inside such things, you take 1d12 force damage. 

You can use this feature once, and you regain all expended uses after a long rest. 

One With the Shadows

Starting at 17th level, you are now part of the shadows. Whenever you are in dim light or darkness, you can use an action turn invisible. This invisibility ends if you make an attack, or force a creature to make a saving throw.