Changelings are infant Fae swapped discreetly for infant humans. They grow to resemble the people who raise them, as a result of eating human food, and being separated from Fae influences. The "infant" Fae would likely not have been truly a newborn, but a Fae convinced entirely that it is an infant human. Whatever lives they lived before becoming changelings are forgotten, as is typical of Fae who shift into drastically different forms. These changelings are often very difficult to raise, and never lose their fae-spirit. They are wild, curious, uncoöperative, and typically disinterested in learning to read, write, do math, etc. They are, however, intensely social by nature, and have a carefree approach to life. They tend to have a wanderlust that drives them to travel from a young age.
That is to say, the changeling appears to age at a rate typical for a human. The changeling will have convinced itself so thoroughly that it is a mortal human that they may even appear to "die" if seriously injured. This works in reverse as well. If an attack is not convincingly injurious, the changeling may ignore it. Certain types of magical effects are thusly ineffective on changelings, even if they typically work on other Fae. While it is inevitable that a changeling eventually discovers her true nature, they tend to be very slow to being convinced of it, and may even carry on their lives as usual after finding out. However, once a changeling is made aware of their nature as fae, certain fae characteristics may begin to present themselves- specifically the tendency for Fae to change in form overtime to fit their desires or behavior.
The human children who the Fae "infants" are swapped for are similarly usually raised in the Greenwood believing they are Fae themselves. Raised eating fae food, they tend to take on fae qualities, and usually remain child-like in form, with greatly extended lifespans. These children are also sometimes known as "changelings" but are more formally known as Fae-Touched.
