Changelings can shift their forms with a thought, so long as it's still a humanoid form. Their true form lacks detail and their skin tone is white or light-grey. Their eyes are colorless with black rings, and their hair only grows atop their head, which generally is a pale silver, platinum or blonde. Rarely they have pink, blue or green hair. Their natural form is slender and an average height of 5'6"

They are descended from doppelgangers. There are a few ways of reproduction, that of their parents being a human and doppelganger. However, some changelings can be from a line of humans for generations. The DNA to become a changeling is recessive so both parents must have the heterozygote allele, making it rare but possible to birth a changeling.

Mature faster than humans, and while they have the ability to alter than physical age - it still affects their true form.

Many changelings use their gifts as a form of emotional or artistic expression. However, they can easily be as spies or criminals with their shifting ability. They prefer to keep low profiles and not take a passionate stance, and easily adapt to the culture they are raised. They are cautious and only take risks when they believe their chances are worth it. They are commonly harmless and passive people that do not care about social status, and they avoid confrontation or anything making them the center of attention.    Due to their way of life they are mistrusted by other races. This makes changelings feel isolated and forced to create fake identiies. They generally choose to  create an entire new personality rather than shapeshift into someone. They tend to have a variety of different 'alters' so they can easily dissaper and switch between them to avoid controversy. These 'alters' tend to have different communities, friendships, personality traits, and completely different backgrounds. Making it difficult for the changeling to learn what was originally their own personality. The way of using their gift was taught by their parents to help them adapt and not be harmed, or to make the parent feel more comfortable with a changeling child.

Varies

Not much of changelings is recorded in history. However, through oral history and gossip they are considered untrustworthy, criminals and thieves. This makes them more likely to be ostracized or prejudiced in society which is why changelings rarely show their true form.