Fetch

To lay thine eyes upon a fetch, apparitions bearing uncanny resemblance, can only be a herald of doom. Fetch rogues walk amongst their prey, wearing the faces of friends & family. They do not hide in shadows, but behind the smile of a trusted confidant or the deference of a loyal servant. Then, when their target is at their most defenceless, they leave them bleeding in betrayal, killed by a creature of nightmare & superstition...

 

[Taken from Faerie - A Realm Wanderer's Guide]

Many Faces

As a bonus action you can change your face and form to that of a creature you have seen before, or have a detailed description of. This creature must share the same number and arrangement of limbs as you, and be of the same size as you or one size smaller or larger. Changing in this way tangibly shifts your entire appearance, including your face, voice & clothing,
however you gain no mechanical benefit from the changes.

While you are in the form of another, you have advantage on any skill checks made to mimic their mannerisms to avoid detection as an imposter.

Sudden Reveal

While wearing the form of another, you gain advantage on attack rolls against any creature who considers your stolen form to be an ally, provided that they do not know you are an imposter.

If you hit a creature with an attack whilst undiscovered in the guise of their ally, they are also considered surprised until the end of their next turn, and the attack is automatically a critical hit.

Imitation Art

If you take the hide action whilst within 5 foot of a creature whose form you are wearing, you instead use the chaos of combat to confuse their allies as to who is the original. Roll Charisma (Deception) contested by a creature's passive Insight. Your first attack against a creature fooled by this deception is made with advantage, and any creature who targets you with an attack or spell whilst fooled must first roll 1d6. On a 4 or higher, they instead target the original creature. The deception remains until you target a deceived creature with an attack, or are otherwise discovered as an imposter.

Additionally, your illusory mimicry is no longer detectable by divination magic of 5th level or lower.

Mirror Of Madness

Seeing a spectre of one's self is an omen of a terrible fate, it's even enough to drive someone mad. If you hit a creature with a melee sneak attack whilst wearing their form, they must make a Wisdom saving throw (DC 8 + Charisma modifier + proficiency bonus). On a failure, the creature becomes haunted for one minute, until your guise changes, or you take the hide action.

While haunted, the creature has disadvantage on attack rolls against you, and you have advantage on attack rolls against them. If you score a critical hit against a haunted creature, it gains one short-term madness effect until the end of its next turn, after which they are no longer haunted.

A creature that has succumbed to this feature then becomes immune to it for 24 hours.

 

Destroyer Of Dynasties

When you take an action during the first round of combat while wearing the form of a creature allied to your enemies, you may take a number of additional attacks equal to the number of surprised creatures within 15 feet of you. You apply sneak attack to each of these attacks, but may make only one attack against a single creature.