Shifting Form (5e Feat)
From D&D Wiki
When you select this feat, You permanently choose one form of a humanoid creature's subrace of your size; Though you do not gain any of that humanoid’s traits, you gain all the racial features of that said subrace. You also learn one additional language known by the race you chose (if the race can choose any language so can you) and add one additional persona to your repertoire but it must be with the subrace you have chosen. You can only have this feature once.