Spectre

For most, Spectres are a whisper on the wind at night, they are a story that children are told about at night, they are a rebels worst nightmare. In truth, Spectres are engineered assassins. They are picked from the best of the best and then enhanced with the energy of the ethereal. Among the best spies and assassins in existence, if you're being hunted by a Spectre, there is no escape. Undetectable, untouchable and notoriously difficult to prepare against, Spectres are exactly what they claim to be... ghosts.

Phase

Starting at 3rd level, when you use the bonus action granted by your Cunning Action to take the Phase action. When you do so you become semitransparent, you can move through non-magical difficult terrain without expanding any additional movement, and can move through non-magical objects and creatures. If you end your turn inside an object or creature, you are immediately shunted to the nearest unoccupied space that you can occupy and take force damage equal to the number of feet you are moved.

Empowered Phase

Starting at 9th level, you can now Phase through magical terrain, objects and creatures without issue such as those produced by hallucinatory terrain or a Leomund’s tiny hut but not those which extend into the Ethereal Plane such as a wall of force. Additionally you may gain advantage on the next attack you make after you Phase. You can gain advantage in this way a number of times equal to your proficiency bonus. You regain all expended uses of this feature after completing a long rest.

Supernatural Sense

By 13th level, you've displaced yourself so many times that you've developed an otherworldly sense. You can see invisible creatures and objects as if they were visible, and you can see into the Ethereal Plane when you are on the Material Plane, and vice versa. In addition, by heightening your sense to even perceive the Ethereal you have a blindsight range of 30 feet.

Ethereal Phase

Begining at 17th level, you've mastered your ability to Phase. When you Phase, you completely disappear into the Ethereal Plane becoming invisible and unable to produce sound. Any damage you take when you Phase is halved. When you Phase, while on a plane of existence that does not have an Ethereal Plane you create your own centralized version of one, allowing your abilities to be used seamlessly as if there was one.