Fairy Courts
The Seelie and Unseelie Courts By many accounts the beings of Fairy are divided into two courts, the Seelie and Unseelie. This is often simplified as the 'good' and 'bad' fairies The Seelie court is described in relation to the fairies specifically as the "pleasant or happy court, or court of the pleasant and happy people" and is also given as a general term for all fairies
The Unseelie court is for all intents and purposes the antithesis of the Seelie court, as implied by the name. The Unseelie court is described as always unfavorable to humans and is closely linked to the Sluagh sidhe, the malicious Host who torment people and cause illness and death where they visit.