Seelie & Unseelie

The Fairie world is divided into two courts, two moral codes if you will, the first is the Seelie; such creatures are friendly and inquisitive to humans more likely to help than hinder us, though they still like to play tricks on people and should never be fully trusted.
Unseelie are openly malevolent towards humans and love to torment us, if they spare your life it is only so they may keep you as a pet.