His kindred, the Dáirine or Corcu Loígde, believed to be related to the Érainn, provided a number of powerful kings of Tara in the early period, and this could not be ignored by the Uí Néill compilers of the list.
Deda mac Sin (Deda, son of Sen) was a prehistoric king of the Érainn of Ireland, possibly of the 1st century BC.
The Dedu (Clanna Dedad) is another name for the Érainn, the tribal grouping which gave their name to Ireland.