FAERIE

Don't give a faerie your name.

"The difference between fairy and faerie is that a fairy is a young, kind and pure spirit whereas a faerie is a mischievous, evil, and horrid creature."

Names hold power.

"If a faerie asks for your name and you tell them, you're giving them power (and possibly complete control) over you. ... However, if you know their name and say it, then they will leave you alone."