There is one Demi-Fey Court in the Unseelie Court and one in the Seelie Court.
Unseelie Court[]
Demi-Fey Court of the Unseelie Court is one of the smaller courts within the Unseelie Court. Its ruler has a title of Queen/King. The current ruler is Queen Niceven.
Seelie Court[]
Demi-Fey Court of the Seelie Court belongs to the Seelie Court. Its ruler does not have a title of Queen/King anymore. It is led by a duchess.
This court it mentioned in A Shiver of Light.