Polymorphs (alternatively spelled Polymorfs) are rare Changelings that can shapeshift into anyone without a familiar.
Like changelings, polymorphs can live among people while in human form.
Physical Description 
Polymorphs are mostly similar to ordinary Changelings, expect that polymorphs are able to take any other shapes rather than just their familiars. They are never seen in their true forms (or if they even have one).
Powers & Abilities
Polymorphs are able to change their forms into anyone of their choosing, human and troll alike, rather than just their human familiars.
|Appearances in the Trilogy|
- Otto stated that being a Polymorph is one of the perks of being the Grand Commandant, indicating this may be an ability granted to high-ranked enough changelings, rather than an actual different species.