Demal mac Rothechtaid, was the son of Rothechtaid mac Main, who, according to medieval legend and tradition, was a High King of Ireland.
His son was Dian mac Demal, his son was Sírna Sáeglach mac Dian - High King of Ireland, his son was Ailill Olcháin mac Sirna - King of Ireland.
References
Demal mac Rothechtaid Wikipedia(Text) CC BY-SA