Not a DND expert but generally the trope with Fey is that their magic uses people’s names so If a fey knows your name they can do whatever they want to you.

To piggyback on previous responses, a common trick I’ve seen in Feywild games is when introducing a new Fey, they would say “You can call me ArgleBargle, may I have your name?”

The trick is that if you give your name to someone in the Feywild, it is no longer yours.

trans people wielding immense power in the fae wilds