Cailean, also known as Colin and Nicholaus of Carrick, predeceased his father and therefore upon Donnchadh's death in 1250, the title of Mormaer came to Niall.
It would also explain the strong alliance with the Ó Neill held by Niall's grandsons.
[2] As the son of Cailean, Niall had one sister, Afraig, who married Gilleasbaig of Menstrie, a baron of Clackmannanshire who was the first attested man to bear the surname "Campbell".
[3][4] On 12 September 1255 Níall, having no male heirs, granted the chiefship of the clan to his nephew Roland and his heirs, giving them all the powers in respect to the ceann ceneóil (head of kin).
[5] Niall died in 1256 and was succeeded by his daughter Marjory, who took the title 3rd Countess of Carrick.