He was married to Garbae ingine Néilléne of the Cenél nEógain. He had five sons including Fiachnae mac Demmáin (died 627), a later king of Ulaid. His descendants the Clan Demmáin went on to monopolize the kingship of the Dál Fiatach. His fort, Ráth Deamáin, stood just west of Crossgar in what is now the townland of Rademan in the parish of Kilmore, County Down, Northern Ireland.
