Weaknesses and Drawbacks All Changelings are affected by the ancient bane of the fae, Cold Iron. Its presence makes changelings ill at ease, and cold iron weapons cause horrible, smoking wounds that rob changelings of Glamour and threaten their very existence with Final Death.
Changelings are vulnerable to iron weaponry inasmuch as their mystical defenses, coming as they do from the same source as the Others', are of no use against it, but they do not suffer from the deep-seated loathing of the substance that binds the Gentry.
If you regularly notice paranormal activity and are rarely phased by it, you may be a changeling. You do not have to see them to feel that they are there. Frequent nightmares and difficulty to sleep at night may also be a sign. Changelings sometimes develop nocturnal tendencies.
Changelings live as long as mortals do. The fae soul that is in the body is 'immortal' in that it will return to the dreaming to be reincarnated again and again but, the body it inhabits is just as mortal as say a werewolf is or a mage.
Shapeshifting – Changelings can appear human, and are capable of shifting between forms in order to feed. Sharp teeth – Changelings have a lamprey-like mouth covered in sharp teeth that allow them to feed on humans. Super strength – Changelings have superior strength compared to humans.
Fire - Setting a changeling on fire will kill it. Family - Killing a mother changeling will cause its children to die instantly. Mirrors - A changeling's true form is revealed in a mirror. Magic - Fairies are susceptible to the powers of magic.
WotC has confirmed that changelings are considered to have the Shapechanger subtype. So they are indeed immune to polymorph and can be affected by moonbeam.
Within this description there are variants of changelings that show subtle differences. Some have opalescence in their skin (as if it contains various colors instead of just being white) and their eyes can be completely black.
Although they're not affected by sunlight at all, a Changeling's most common weakness are Gaggletacks (horseshoes made of pure iron), which reveals a changeling's true nature through physical contact of anywhere on the body.
They have large colorless eyes circled by thick black rings. Their hair color is most commonly a light shade of silver followed by platinum and blonde. In rarer cases, their hair can be pale shades of green, pink, and blue. Similar to elves, changelings lack body and facial hair.
Changeling Reproduction
If a changeling with the Racial Emulation feat matches its subtype to that of a partner, a child resulting from the union will always be of that humanoid subtype. If a changeling in a female form conceives a child, she loses the ability to change her gender until after the child is born.
Changelings born from two changeling parents are born in their natural form: pale, slender, with colorless eyes and white hair.
Changelings have the unique ability to transform their body to look however they want, provided they keep the same arrangement of limbs they already possess. It is very rare to actually see a changeling in it's 'true' appearance. Even when disguised, changelings can instinctively recognize each other.
Weapons and implements made from cold iron are often granted special efficacy against creatures such as fairies and spirits. In the Disney film Maleficent, the title character reveals early on that iron is lethal to fairies, and that the metal burns them on contact.
Some have suggested that this is where the myth of the fairy folk began. These 'fairy folk' who used 'magical' tactics were armed with bronze, which was no match for the iron blades of the invaders. Therefore, iron became known as the enemy of the 'fairy folk. '
A changeling can't make the wings at all. If they had wings, like from a class feature or something, then they could look like an Aaracokra with wings because they will have those limbs at that point.
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.
A changeling can eliminate or add traditional physical disfigurements - such as scars or birthmarks - when changing shape.
Obviously, a changeling's appearance can change at any moment, but they do have a true form. Their true skin is usually grey or pale white, and their facial features are blank slates to an unnerving degree. They're typically thin and gaunt, and their hair is usually silvery with an occasional green or pink tint.
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.
By RAW changelings revert when they DIE but not when they are unconscious (it would be hard to maintain a long term masquerade if you revert when you sleep!).
They also have more physical differences among them: some possess longer, more jagged horns, and others no longer have horns at all. Others still no longer have tails. Some also have a trio of gemstone-like objects in their chests. Like Queen Chrysalis, the changelings were designed by Rebecca Dart.
"A human child might be taken due to many factors: to act as a servant, the love of a human child, or malice. Most often it was thought that fairies exchanged the children.
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.
Age. 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.