Changelings are thought to be an uncommon race—though their true demographics remain unknown, as may live their entire lives masking as other sentient races. Many places in the world fear changelings for their unique ability to assume the form, or 'profile', of nearly any person, indefinitely.
A changeling is typically identifiable via a number of traits; in Irish legend, a fairy child may appear sickly and will not grow in size like a normal child, and may have notable physical characteristics such as a beard or long teeth.
A changeling is a child who is suspected to not be a couple's real child. As the myth goes, a changeling was substituted by fairies.
Most changelings don't know they're changelings.
Though they may always feel somewhat different or removed from human life, most changelings are too young to understand who they truly are.
Changelings cannot alter themselves enough to change physical sizes (i.e, changing from Medium to Small, etc). It is worth noting that while a changeling could technically shift into something like an aarakocra, their wings would be non-functional.
The new child—the changeling—is characterised by unresponsiveness, resistance to physical affection, obstreperousness, inability to express emotion, and unexplained crying and physical changes such as rigidity and deformity. Some are unable to speak.
Changelings born from two changeling parents are born in their natural form: pale, slender, with colorless eyes and white hair.
Unlike doppelgangers, which are entirely genderless, a changeling does have a default gender that manifests in adolescence, but each changeling can adapt his or her form to be of either gender, hermaphroditic (both genders simultaneously), or entirely genderless.
Changelings reach maturity slightly faster than humans and live as long as humans do, typically about 100 years.
Changelings have red blood like a majority of the other races. Bleeding around others may alert many that the Changeling is not of the same race (should the blood color vary). For this reason, a Changeling will usually choose to take the form of a race with red blood.
Changelings were fairies who had been left in place of a human child or baby who had been stolen by the fairies. The child was taken for one of three reasons; to act as a servant, for the fairies to receive the love of a human child, or for malice/revenge.
As for being tattooed, changelings can definitely be tattooed, and they can just as easily erase the tattoo with a moment's thought.
The short version is that a Changeling can shapeshift to a form that can produce sperm to impregnate someone, and can shapeshift to a form with a uterus and eggs to get pregnant, but a pregnant Changeling cannot shapechange to a form without a uterus without ending the pregnancy.
Appearance. In their true form, or their form "at rest", changelings have pale skin, colorless eyes that can be completely white or completely black, and white or silver-white hair.
In their true form, changelings are generally extremely pale, showing features devoid of distinctive details, with colorless eyes and silver-white hair.
Changelings typically have large eyes with narrow pupils, ranging in color from white, to yellow, to black. Hair colors are similar: Light grey, platinum blonde, shades of silver, all the way to the darkest hair color being a light brown.
Changelings mature slightly faster than humans but share a similar lifespan—typically a century or less. While a changeling can transform to conceal their age, the effects of aging affect them similarly to humans.
Changelings lay their eggs directly within food sources her offspring will eat after hatching - namely stashes of meat - that the mother has procured and hidden out of sight in a secure place, such as the abandoned burrow of some small animal, a crevice in rock, or a small hollow in a tree.
You can appear as a member of another humanoid race which will include things like tails, frills, gills, wings, horns, etc. However, your stats do not change so you cannot use the tail prehensively, cannot breathe underwater with the gills and cannot fly with the wings.
Size. In their natural forms, changelings average between 5 and 6 feet in height, with a slender build. Your size is Medium.
If a savvy investigator gets suspicious of you, there's a method available to them that allows them to determine your guilt with certainty: the blood test. Changeling blood is different from human blood. It reacts to strong heat. If someone is allowed to draw your blood and heat it, you'll be revealed as a changeling.
Halflings are a rare species that occurs when a faerie fraternizes with a human. These hybrids possess limited fae powers and have high attraction to and from the supernatural. They also have "fairy godparents" to protect and guide them.
When the human part of a changeling dies (Banal Death), the fae self may live on, but that changeling will never come into existence again. Commoners are reborn into another human host who has a different appearance and upbringing from the previous mortal seeming.