Changlings

Changelings were a fey or humanoid race related to doppelgangers who had a natural ability for shapeshifting, making them effective as actors, spies, and criminals.

Changelings were subtle and deceptive in their ways.How a changeling chose and used each new guise they adopted was up to each individual. It might be for mischief, for entertainment, or for heroism, or it could be for terrible misdeeds. To one changeling, it might be no more than a disguise, but to another, it could be another facet of their soul. They had different terms for different kinds of guise. A 'mask' was a guise that lacked a backstory and deeper personality; it was created on a whim to display a mood or to fulfill a need and could be discarded, never seen again. A 'persona' was a full identity with a backstory, depth, and beliefs of its own. A changeling could maintain a number of personas for different applications and situations, and changelings and changeling communities could share them (for example, three changeling healers could play the one physician persona in shifts) or bequeath them to their descendants (so a young changeling could have the benefits and contacts of an older persona).

Changelings had the magical ability to change their appearance. Although similar in effect to a disguise self spell, this was no illusion but a small physical transformation of their bodies, so their clothing and possessions are unaffected.

For more info:MoM book DnD 5e