*Fergus Mor MacEarca "The Great" King of Ireland & Scotland
born about 0430
died 0501 Dalriada, Argyll, Scotland

father (possibly):
*Muireadhach of Ireland
or
(likely)
*Earc MacEochaid King of Dalriada
born about 0400 probably Ireland
died 0474

mother:
*Misi (Mist) wife of Earc MacEochaid
(end of information)

siblings:
*Loarn Mor King of Dalriada born about 0432 Scotland
Angus MacEearc born about 0435

spouse:
unknown

children:
*Donart (Domangart) of Scotland

biographical and/or anecdotal:
HBJ which is generally well-researched quotes:
In 498 A.D., with five of his brothers, he went into Scotland with a complete army to assist his grandfather *Eóghanr (Loarn or Owen) Find macNéill King of Dalraide, in overcoming his enemies, the Picts. Upon the King's death, Fergus was unanimously elected king, and became the first absolute king of Scotland, of the Milesian race.
This sounds like a Victorian romance however and it is more likely according to "Biographical Encyclopedia of the Kings & Queens of Great Britain" by Mike Ashley
That his father was Earc of Dalriada. His name (MacEarc) indicates this as well.

notes or source:
HBJ