The Tuatha De Danann lived in Ireland ages ago, before the first humans were born. After a long reign they were defeated by the Milesians. The Daoine Sidhe, those that remained after the defeat, live in mounds in the earth. They're supposed to be very fond of battle, hurling, and chess.

The Daoine Sidhe are divided into two groups, the Seelie or "blessed ones", who are considered aristocrats, and the Unseelie or "unblessed ones". Each court has their code, but the Seelie are considered to be 'good' fairies because they're fond of humans and don't usually harm them. The Unseelie are considered 'bad' fairies because they do the opposite.