Swiftblade

Such bladework is oft of utter keenness that its victims know not that they have been hewn; or even if they are somehow cognizant of the fact, they are affixed by a bladetrail that has seized the space they inhabit, only to bleed when the moment passes.
Yet… the difference lies in how it cuts.
The blade has indeed hewn but a singular trace, yet in sheathing it the wielder has conjured in their mind the multitude of slashes that have followed the same path—a most precise technique.

 

With deft hands and deft eyes, rogues who practice the Arts of the Swiftblade with single-minded obsession are said to cut through space itself, in a manner untraceable and unrecoverable.

Level 3: Singular Slash

Your walking speed increases by 5 ft.

At the start of your turn, you can choose to enter a special state called Bladetrails till the start of your next turn. You cannot use your Sneak Attack feature whenever you hit an enemy while Bladetrails is active. Instead, at the start of your next turn, you automatically use your bonus action to end Bladetrails. When you do so, choose one creature you hit between your last turn and current turn. You deal your choice of Slashing or Force damage to them. This damage is a number of d4s equal to the number of Sneak Attack dice you have multiplied by the number of hits you have made using melee attacks with a finesse weapon. You then additionally deal a number of d4s of Slashing or Force damage to that target equal to your proficiency bonus.

The maximum number of hits that can count towards the damage calculation of Bladetrails is equal to half your Rogue level (rounded up). Also, you cannot enter the Bladetrails state in the same turn as you use the bonus action to end it.

You can use this feature a number of times equal to your proficiency bonus and you regain all uses of this feature after a short or long rest.

Level 9: Invariable Paths

Your walking speed increases by 5 ft.

Immediately after using either the Sneak Attack or Singular Slash feature for dealing damage, you can choose to summon an illusory copy of yourself within 10 feet of an enemy of your choice that you can reach with your movement speed. The illusory copy will assume a combat stance and follow the enemy around if they move. This illusory copy is easily distinguishable from you, and lasts till the end of your next turn or until after you make one attack against the designated enemy.

If you choose to attack the creature currently being targeted by the illusory copy, you gain advantage on your first melee attack roll with a finesse weapon against it. If you hit, the attack counts as 2 hits for the Bladetrails state if it is active, or deals 1d6 extra Slashing or Force damage if Bladetrails is inactive.

At level 13 and 17, when you use this feature, you create 2 and 3 illusory copies of yourself respectively. These copies can target the same enemy or different enemies as you choose. When you attack an enemy that has multiple illusory copies surrounding it and you hit it, the attack counts as (1 + the number of copies surrounding the target) hits for the Bladetrails state if it is active, and deals (number of copies surrounding the target)d6 extra Slashing or Force damage if it is inactive.

Level 13: Echoshear

Your speed increases by 5 ft.

While the Invariable Paths feature is active, before you take the Attack action you can choose to teleport to the location of one of your illusory copies. When you do so, all effects of Invariable Paths end immediately, and you can make one attack against the creature that was formerly targeted by the illusory copy whose space you currently occupy. If you hit and meet the requisite conditions, this attack counts as two hits for the Bladetrails state, and one more hit per condition fulfilled:

• The attack roll had advantage.
• The attack was a critical hit.
• You had the Invisible condition before making the attack.
• Either you or your target are Bloodied. 

You can also use your Sneak Attack feature on this attack as long as you meet its requirements, even if the Bladetrails state is active. However, using this feature for Sneak Attack does not activate the Invariable Paths feature.

Level 17: Purity

Your walking speed increases by 5 ft.

While the Bladetrails state is active, as an action you can choose to teleport to a location you can see that you can reach with your movement speed. When you do so, you unleash a whirlwind of slashes in a straight line from your initial position to your current position with the width of the line being your reach, as well as in a radius equal to your reach at the initial and current position. You make two attacks with a finesse melee weapon you are holding against every creature within the area of effect, and these attacks deal 0 damage on hit. When the Bladetrails state ends next turn, you can choose any number of creatures you hit with this feature, and apply the damage from the Singular Slash feature to all of them.

If you choose to apply the damage from this feature to only one creature, the maximum limit of hits for your Singular Slash feature is increased by 3 for this use, and you can treat a roll of 1 or 2 on the damage dice as 3.

Once you have used this feature, you cannot use it again till you have completed a short or long rest, or if you reduce an enemy's HP to 0.