Both the accounts agree that he was descended from Collwyn ab Tangno, 'lord of Eifionydd, Ardudwy, and part of Llyen.'
The appellation of blaidd (wolf) was inherited from his maternal grandmother, Haer, daughter and heiress of Cynfyn, son of Cillyn y Blaidd Rhudd (meaning "Cillyn the Bloody Wolf") of Gest in Eifionydd.