Plane Shifter

Abilities that are considered unnatural, planeshifters gain their powers from equally unnatural means. Experiments gone wrong, curses, etc. Planeshifters are looked upon not as equals but as tools and objects to be used. The powers of the shifter being tied to weaving a web between the ethereal plane only they can walk, albeit unstably. The planeshifter strikes fast and leaves even faster, darting around the battlefield using their unnatural abilities to their own benefit.

Ethereal Dash

At 3rd level, you gain the ability to dart briefly into the ethereal plane. When you take the dash action, you can dash through the ethereal plane, moving up to 60 feet total with your dash in the ethereal plane. You lose your normal movement when you take this action, and can only move in a dash. You can move in any direction in your dash, but are subject to the effects of coming out of the plane. (i.e. if you choose to use all your movement to move up 60 feet, you will fall 60 feet). While dashing, you do not trigger opportunity attacks unless a creature is able to see into the ethereal plane. You can not dash through objects you would not be able to get through in the material plane, but if something weak and transparent is in your way, you can go through it without breaking it (i.e. you can not go through stone walls, heavy doors, or certain magical effects, but you can go through a closed glass window)  If you are interrupted while dashing, the strain it takes on you forces you to spend your next turn unable to dash, your movement speed is halved, and you can only take an action or bonus action, not both. Additionally, if you come out of your dash next to a single target and are within 5 feet, you may trigger your sneak attack. 

Ethereal Body

Also at 3rd level, you become hard to locate and perceive. Wisdom (Perception) checks or Intelligence (Investigation) checks made to find you or traces of you are done at disadvantage, and magical location effects must make a Wisdom check against your save DC to be able to locate you. (Save DC is 8 + Dexterity Modifier + Proficiency).

Ethereal Grace

At 9th level, your control over your unstable nature has progressed to increased levels. You can now move 90 feet in your dash. Additionally, effects made to planar shift you against your will no longer work.

Ethereal Resident

At 13th level, you have controlled your ability to enter the Ethereal to a fine degree. You can now cast the spell Etherealness at will, once per day, without expending a spell slot or material components. You can also take one willing creature you can touch with you. 

Depth Strider

At 17th level, you can briefly pierce the veil into the Deep Ethereal. You can enter the Deep Ethereal during a short rest to replenish your health, and may regain up to 5 times your Rogue level in hitpoints (Ethereal Mending). Additionally, when you hit a creature with a sneak attack, you can send them to the Deep Ethereal for 1 minute. The target returns in the space it left from after this time, and takes 8d6 force and 8d6 psychic damage (Ethereal Rending).

 

These properties can be used once per long rest each.