The first thing that separates changelings from most people is the moment they are physically removed from the "real" world. Most folks have no idea that other realms exist and have never conceived of a barrier realm like the Hedge. After all, modern fairy tales refer to otherworldly beings like Rumpelstiltskin, but they rarely talk about where those beings came from. Fewer still claim that the faerie world and its denizens are real. So the very possibility of going somewhere else is mind-bending enough, but being dragged there by beings that should not exist makes everything worse.
The way a changeling first encountered Fae creatures and entered their jail sentence in Arcadia (called a Durance) can explain a lot about their quirks and motivations. A character who was doing something they shouldn't have been doing might carry a deep self-loathing hidden under layers of denial. A character who was lured by magical drugs might be glad for freedom, but desperate for the old high - a high that cannot be reached by mundane intoxicants. Yet another changeling might have been the concubine of an angelic-looking Keeper, and thus finds ordinary humans to be inferior partners.
This can translate into the choices a character makes after they escape and the way that dots are placed on a starting character sheet. It also reveals insights into the type of Keeper or parties involved, and tactics that might be used against the character again. The Keeper that relies on privateers to capture a changleling once will likely use third parties to bring them back. A Keeper that trapped a changeling in an intricate ploy once might try to do so again.
Some of the most terrifying stories come from changelings who were snatched violently from their lives and thrust, bleeding and screaming, into the otherworldly. The application of physical violence isn't always necessary, especially given the powers of True Fae and hedge creatures, but the hunt is part of the thrill. Privateers might resort to force when they're working quickly or if they're under a very tight deadline.
Where: True Fae don't tend to ride into crowds and beat their way to prisoners; they stay off the general radar and isolate their prey. Violent abductions might happen so quickly that no one has a chance to react, such as when a scream in an alley gets cut off. Or the bloodshed might be contained inside a few flimsy walls; while a man is beaten and dragged to a mirror, neighbors outside seem to hear nothing. These kinds of details can stand out nicely in a prelude.
Who: Whoever's around when the blood starts flowing stands to be abused, as well. Was the character's family killed? Were they hurt and kidnapped, too? Did anybody manage to get away? Or was the character completely alone to face her fate?
What Happened Next: Were the police called when the character was being beaten within an inch of her life? Did an officer show up, only to be punished for interfering? Did the police write the character off for dead or list her as missing?
Sometimes people are tricked into entering a house, signing their name to a contract, or otherwise putting themselves at the mercy of the Fae. Unfortunately for them, the Fae have no mercy and are exceptionally crafty. They are masters of words and find a way of entering at just the right moment. Just lost your job? Why not go with the nice gentleman who promises to pay three times as much?
What: With this scenario, it's important to figure out what sort of deception was involved. Was it a simple lie or misdirection, or was it a elaborate design? Was anyone else in on it?
How Much: A character might uncover the ruse a little too late, but it is possible that they don't know as much as they think. Perhaps they never got a good look at the goblin merchants or they didn't realize their Keeper was haunting their dreams. Are there details yet to be revealed?
How: It is also helpful to consider how the character reacts to deception after returning home. Is a lie even worse because the character was tricked out of their life? Or does the character strive to be the best liar ever, so he'll never be tricked again?
Not all Keepers or privateers seem horrible or dangerous. Some can be downright beautiful, charming, and pleasure-seeking, offering a character the time of their life. Some Fae know how much humans like material wealth and lure the unwary with gifts while others offer burgeoning addicts all the drugs they desire. These enemies can be among the most subtle and the most effective, particularly if they allow changelings some pleasures in Arcadia. Why go back home when the best high you've ever had comes from your master's garden?
What: Which pleasures was the character allowed? There are more ways to seduce than meet the eye and they are not all tied to sex. Perhaps the character fell in love with hedge fruits and wants to gorge on them whenever given the chance (and no more mom nagging about getting fat). Or maybe the character followed their Keeper into the hedge to consummate their relationship. Worse yet, maybe the character was allowed to indulge in forbidden desires they hid from others out of fear of the law.
It is one thing to be misdirected by a god-like being, and another thing to be betrayed by a mortal you trusted or didn't think was a threat. Privateers are bad enough when they're strangers, showing up in unassuming guises. The woman who asks a character to spend the night might sell him to a goblin market without feeling too bad, since he was only thinking of his own good time. But family and friends can also sell you down the river, and that makes coming back even worse. How do you ever trust or forgive anyone ever again?
Who: The closer the bond, the worse the sense of injustice and horror. Think about all the people in someone's life, from their parents to their friends, and consider why a person would sell someone close to them. Also think about people who might be discounted, like siblings, cousins, and teachers.
What: What was the motivation for the betrayal? Was it a matter of revenge, punishment, or not-quite-just desserts? Did the character invite an attack, only to get in over their head? Was the betrayer willing or unwilling? Some people are threatened into giving someone over and feel they have no choice.
How Much: Does the character know who betrayed them, and how did they find out? Were there details they weren't aware of? Did other family or friends know about the lies and danger? Did anyone try to warn them?
How: It is also helpful to consider how the character reacts to deception after returning home. Will they hunt the person who sold them out before going after their fetch? How have things changed while they were gone?
A number of changelings were taken because they went somewhere or took something they weren't supposed to. The Gentry are unforgiving with trespassers, without exception. (In an older version of La Belle et la Bête, Belle's father becomes lost and takes shelter in a castle. He eats a meal laid out on a table, which might have been forgiven a wayfarer, but makes the mistake of picking a rose from the Beast's garden without the master's permission. It is that act that enrages the Beast and causes him to demand that the old man send his daughter to live at the castle as payment.) The Others also don't appreciate thieves, the way that Minerva didn't appreciate Arachne's errant boasts - with similarly violent results.
How: How and where did the changeling trespass? Did they understand that they weren't supposed to cross the boundaries? Were there warning signs that they refused to heed or actively worked against? If they were seeking a reward of some kind, what was it they fancied? Did they have any idea what they wanted was owned by an otherworldly creature?
What: What were the terms given for punishment, if any? Was the changeling supposed to serve ten years for every gem they tried to steal? Were they promised freedom if they could infiltrate another Keeper's realm and return with a favored token?
Not everyone ends up in a Keeper's hands on purpose. This last category isn't for typical abductions but for stupid accidents that nonetheless end up in Durances. Good Judge Whitlock didn't know that thinking of an old tune while walking between two particular trees lining Chicago's Midway Plaisance would allow him entry into the Hedge, but once he was lost and confused, he was easy prey. Bobbi somehow gained her Keeper's attention by opening a door for him through her special gifts. Similar accidents happen every day, somewhere, to some poor, unfortunate soul - so they should be kept in mind.
Where: Location can be important to this type of occurrence. So where did things start to go wrong, and why? Did the character ever figure out what they did to end up in such a bad predicament?
What: What was it that ended up finding the character? It might have been a hedge creature, or hobgoblins. The first stop might have been a goblin market, with a Keeper entering the picture much later.