Specter

Some rouges just don't like the odds that come with being stuck on the material plane. Some find solace in the Ethereal Plane, many of the rouges from this archetype go many different ways. Some are specialize assassins, some are thieves some are even spies. Rumors float around that the first specter was personally taught by gnome Thief by the name of Noxtrim. The end result is these specters have unique ways of getting in and out of places and are generally ones you don't want after you. 

Phase Strike

At 3rd Level, the specter gains the ability to surpass physical defenses, When you make an sneak attack your damage is now Psionic damage instead of physical. 

Ethereal Movement

At 3rd Level, when you use your Cunning Action you have extra affects to them. The following are the changes made to the Cunning Action :

• When you use your Dash action, you phase in ad out of reality allowing you to ignore Difficult Terrain, this also allows you to move through objects that are less than 5 ft thick or creatures. If you end your turn in an object you are immediately forced out taking 2D6 of Bludgeoning Damage. Because your not completely incorporeal and you are phasing in and out if you move past a creature that is considered an enemy and you leave their reach you still take an Opportunity Attack, although they are at Disadvantage to hit you.  
• When you use the Disengage you Blink to the Location, This isn't the spell, rather an ability that mimics the spell. You are still restricted by you movement as to how far you can blink. You must be able to see the spot in which you are blinking. You may split up to half your movement, meaning you can blink and then move the rest or you can move then blink. 
• When you use the Hide, if you have used either your dash or disengage and you either blink into a spot that would be considered more than 50% cover or phase through an object that can be considered at least 50% cover you gain advantage on your Hide Check.

Eyes of the Ethereal

At 9th level, you can now change the composition of your eyes, in doing this they go completely White with a soft violet color. You can use this 2/day, as a Action when you activate this feature you gain the following benefits:

• You can see invisible objects and creatures up to 15 ft. from you. 
• You can see into the Ethereal Realm while on the Material plane and via versa
• You gain while this feature is active Blindsight up to 15 ft. 

This last for rounds equal to your Intelligence Modifier, after which you must finish a shot or Long rest before using it again. 

Walk the Ethereal

At 13th Level, you can now fully phase into the Ethereal plane for a short time. As an action you phase your body, to everyone that see's you you vanish from sight While on the Ethereal Plane, you can only affect and be affected by other creatures on that plane. Creatures that aren't on the Ethereal Plane can't perceive you and can't interact with you, unless a special ability or magic has given them the ability to do so. You can only spend up to your constitution modifier in rounds there before your are ejected from the Plane,  you are ejected from the plane at the end of your turn. When you leave the the plane willing you use a bonus action to do so. 

Specter's Strike

At 17th Level, you now can with deathly vengeance. As an action you can Attack the very soul of your target. On one of strikes that hits a creature they make a Constitution check DC 17. On a failed save, any damage they took reduces their Maximum Health by the amount of Damage you dealt, the health returns after a long rest. 

Recharge 6; You may not use this ability again until you roll a 6 on a D6. This is only rolled at the begin of your turn.