Shadow's Death

The Rogue has never been seen when using the shadows. Using cunning, speed and stealth Shadow's Death subclass makes becoming  a shadow of dark smoke seem like a reality.  Using the skills at the right time the Rogue Shadow's Death becomes a deadly arm of the Shadow Plane in the realm of reality. 

Shadowfell

Choosing Shadow Death allows the rogue begin learning and interacting with Shadowfell.

We begin with 2 new abilities. Stepping in and Stepping out of shadows. 

Whenever you take a short/long rest you're mind is in the Shadowfell. This allows you to spy  from any shadow within 100' of your location within realm of reality or even keep watch on your body in the realm of reality.

Whenever you physically enter Shadowfell for more than a step you are unaware of what is happening in the realm of reality. 

Shadow's Travels

Movement between shadows in now 3 times your movement speed

Shadowfell's Breach

20' radius of shadow that emits from the character for 2 rounds, any enemy inside must make a Dex saving throw, if fails they have disadvantage on all attacks until they the leave the area of effect or the effect ends. On the casting round, Shadow's Death is completely hidden in Shadowfell. On Shadow's Death next turn, he/she has advantage on Stealth/ hide rolls. They can move freely within the area of effect without using any movement speed as if a shadow themselves. All creatures within the area are given advantage on a hide, but are not hidden from Shadow's Death. 

Shadow's Death may let an ally or creature know the general direction of a target, but if they share Thief's Cant then the knowledge of the location is almost certain. 

Shadow's Assassin

The Shadow's Assassin may take a Shadow Step at allowable range, through the shadows and attack, if an attack on a surprised creature the target must make a constitution saving throw DC 8+ Dex + Proficiency. If successful take Critical from the lowest hit damage and normal from the rest, but if failed the creature takes all Critical damage. Shadow's Assassin then can Shadow Step back to any shadow within 30'.  This ability resets after rolling d4 turns or a short/long rest.