This person is only known from a single charter text of King Mael Coluim IV surviving only in an antiquarian copy. If the text is correct, the 'countess' in question could be either the king's mother, Countess Ada de Warenne, or the king's niece Ada, probably the woman elsewhere known as Ela (both were shortened forms of the personal name Adela). In either case this would be extraordinary. Alternatively, if the reference is an error, the obvious candidate for this person's identity is Ness, son of William, lord of Leuchars. If the comitisse is a mistranscription, William could be 'son of the earl', in which case the earl is likely to be William fitz Duncan, earl of Moray.