By Light, By Night Part 2
The Changeling Way (cont.)
All changelings are capable of changing between at least two forms and many kinds of fae are capable of even greater feats of shape-shifting. Every changeling fae has a normal-looking human form and a fantastical fae form. Assuming the fae form allows a changeling to make use of her supernatural abilities – casting spells, flying, super-strength, etc. – but makes her vulnerable to the various folk charms and wards that humans have used against the fae throughout history (iron being the most infamous). The human form doesn't have the fae vulnerabilities but can't use any powers. Thankfully, there's a means for changelings to spend most of their time in their fae forms without anyone noticing.
Most changelings spend the first twelve to fifteen years of their lives without manifesting their supernatural powers. They might be attracted to fantasy fiction and gaming from an early age, but this has become far less remarkable in the past couple of decades (and gives credence to the “sleeper agents” theory among older fae). It isn’t until a changeling begins puberty that her or his powers begin to manifest and she or he begins to become an outcast in the human world. It’s cold comfort, but the aura of weirdness, of “difference” that separates pubescent changelings from the herd of humanity is actually the first manifestation of a magical defense called the Masque.
All changelings are shape-shifters in one sense or another, and the Masque is a sort of psychic shape-shifting. It is a continuous, unconscious mental command that tells normal humans “Move along; there’s nothing to see here.” It allows a changeling to assume her true fae appearance without being noticed by human beings.
Notice the use of the word “notice.” The Masque doesn’t make changelings invisible or change their physical interactions with the world; it just helps them blend in. A tiny pixie flying through the air might appear to be a bee or butterfly while a towering troll might appear to just be a big dude. If that butterfly lands on some normal person’s nose and begins telling her off, then that normal person is going to see through the Masque. If the troll’s fae form is ten feet tall, then he’s going to have to resume his human form in order to fit in a Mini Cooper.