Rogue Archetype: Stalker in the Mists

Some rare individuals are born with an innate and curiously specific aptitude, allowing them to magically shape and channel ambient vapours as they will. Though a niche talent often overlooked or even left undiscovered in those so blessed, it is nonetheless one with obvious and invaluable applications, particularly for those in military or intelligence endeavours and far less reputable lines of work. While most will rarely exceed a basic affinity with their element, a select few go on to achieve mastery over their gift, allowing them to fundamentally transcend their physical form and join with the roiling shrouds they command.

Mistcaller

At 3rd level, as a bonus action, you can magically conjure fog per the fog cloud spell at a level equal to half your Rogue level (rounded up). You can reduce this effect's duration to 1 minute to waive its concentration component. In addition to its normal properties, this fog ends when you dismiss it as a bonus action or you use this feature again. The fog cannot be dispersed or destroyed, and its area is heavily or lightly obscured (your choice). As a bonus action, you can make the fog's area heavily or lightly obscured, or move it up to 60 feet to a space you can see.

You can use this feature once. You regain all expended uses of this feature when you complete a short or long rest.

You gain an additional use of this feature whenever you gain another feature from this archetype after Rogue level 3.

Ghost in the Fog

At 3rd level, you have advantage on Dexterity (Stealth) checks made while in mist or fog, and on Wisdom (Perception) checks made against creatures or objects in mist or fog.

Furthermore, mist and fog that are natural or that originate from your concentration effects don't obstruct your vision or count as being heavily or lightly obscured to you.

Vanish Into Mist

At 9th level, while in or adjacent to mist or fog, you can magically dissipate into vapour, reforming and teleporting to an unoccupied space you can see in or adjacent to fog or mist within 120 feet as a bonus action, or as a reaction when you take damage, halving the damage taken. If you do, you can then attempt to hide and you have advantage on the first attack you make against any creature you teleported adjacent to in this way until the end of the current turn.

When you use this feature, you can't use it again for 1 minute unless you expend a use of your Mistcaller feature to do so.

One With Fog

At 13th level, fog and mist don't count as being heavily or lightly obscured to you, and you can never be surprised by creatures and objects in them. If such creatures and objects are within 30 feet of you, you have truesight and blindsight against them, and know their exact location.

Furthermore, you can expend a use of your Mistcaller feature to magically transform into mist per the gaseous form spell, or two uses to transform per the wind walk spell. This effect lasts up to 1 hour or until you cease concentrating on it. You can reduce this effect's duration to 1 minute to waive its concentration component; if you do, you can dismiss it as a bonus action.

Stalker's Resurgence

At 17th level, once per long rest, when you are reduced to 0 hit points or killed while in or adjacent to fog or mist, you can magically discorporate into a plume of spectral vapours. If you do, you revive at the start of your next turn, regain a use of your Mistcaller feature and hit points equal to twice your Rogue level, reforming in an unoccupied space in or adjacent to mist or fog within 120 feet. You can then attempt to hide. If you cannot reform in this way, you die.