|Ethnicity||Erin, Sea People|
|Other relations|| Clodagh (daughter-in-law)
Firinne and Ronan (grandchildren)
|Significant Other||Mac Dara|
|Residence||Whiteshore (until death)|
She was the daughter of a fisherman and his wife who had died when Firinne was young. Because of her beauty and her health, she was chosen by Mac Dara to carry his child. He seduced her, and left her afterwards. When Firinne realised who her lover had been, she realised that he would return for her son when he reach seven years of age. She placed the green glass ring on a necklace and placed it around Cathal's neck. She gave him to Lord Murtagh, and asked him to shelter her son and make sure he always wore the ring around his neck and never took it off. Lord Murtagh agreed, and treated Cathal as if he were his own son. He offered Firinne a place in his household as well, but Firinne refused, knowing that it would be through her that Mac Dara would search for Cathal.
When Cathal was seven years old, Mac Dara returned for him, as Firinne expected. Firinne told him that Cathal had died of illness when he was two years old, but Mac Dara did not believe her. Firinne fled to the river bank, and Mac Dara followed her. What occurred then no one fully knew. Firinne was found dead in the river three days later, and it was assumed that she drowned herself. However Willow, a daughter of Mac Dara who gave Clodagh the key to undoing Mac Dara's spell on Cathal, believed that there had been a struggle, and Firinne was killed during it.
- Father: Unnamed fisherman
- Mother: Unnamed fisherman's wife
- Siblings: None
- Spouse: None
- Daughter-in-law: Clodagh
- Heir to Sevenwaters (mentioned)