Pathfinder

You master your abilities to slip in and out of the material plane. Truly sneaky and slippery rogues tend to hone in on this archetype. In addition to flashing in and out of people's view, you learn to take your enemies by surprise by appearing right behind them when they are distracted. Your abilities grant you the power to be anywhere you need to be just at the right moment. 

Rapid Disposition

When you choose this archetype at 3rd level, you learn how to manipulate your form through space. During your turn, when you dash as a bonus action, you step into the ethereal plane and reappear where you end your movement. If you are already in the ethereal plane, you cannot use this feature. (Stepping into the ethereal plane in this way does negate opportunity attacks).

Precise Positioning

Starting at 3rd level, your abilities allow you to find yourself in the right place at just the right time. 

If you enter the material plane directly behind an enemy your size or smaller, you don’t need advantage on the attack roll to use your Sneak Attack against the creature if you are within 5 feet of it and you don’t have disadvantage on the attack roll. All the other rules for Sneak Attack still apply to you.

Dancing Disaster

At 9th level, your mobility and control of your abilities flourish in the midst of combat. You excel at flashing about a fight and taking out your targets with speed and elegance. 

As a reaction on your turn, if you reduce an enemy to zero hit points you can teleport to a place you can see within 30 feet of you. You can use this ability a number of times equal to your dexterity modifier per long rest. 

 

Graceful Landing

Starting at 13th level you can use a bonus action on your turn negate fall damage. 

If the fall is 50 feet or less, you can teleport yourself into the ethereal plane and back to the material plane just in time to reduce the momentum and land safely on the ground. If the fall is greater than 50 feet you must make a Constitution saving throw to concentrate on the ability and teleport safely. The DC is 10 + 1 for every 10 feet you fall above 50 feet. On a success you take no fall damage. On a failure you take regular fall damage you would have taken minus 50 feet of fall damage.  

Teleportation Master

Beginning at 17th level, your mastery of dancing between planes reaches its peak. You can use your regular movement to enter the ethereal plane as you would with Rapid Disposition (Distance can stack if you move and use Rapid Disposition to dash as well). In addition,  you can choose to stay in the ethereal plane until the start of your next turn once per short rest.