Lady Oonagh is the main antagonist in Daughter of the Forest.
In Daughter of the ForestEdit
Lady Oonagh meets Lord Colum when he and his party are staying at Eamonn's holding one night. She bewitches him into falling in love with her and marrying her; her plan being that she will create a child with him that will become Lord of Sevenwaters. Once he has brought her to Sevenwaters, Lady Oonagh bewitches Diarmid, one of Lord Colum's sons, into lusting after her and compels the entire household into doing her bidding. She meets Sorcha, tries interrogating and bewitching her into telling her about Lord Colum's sons, to discover their weak points, but cannot get all the information she wants from her, especially concerning Finbar, due to Sorcha's strength and willpower.
Lady Oonagh and Lord Colum marry, and from then on Oonagh shows her true colours. She causes chaos at Sevenwaters, destroying everything that the children of Sevenwaters hold dear. She forces Sorcha to stop going down to the village to heal their ailments and instead makes her learn to sew finely and play an instrument. When Sorcha disobeys her, Lady Oonagh orders that all her herbs, healing equipment and garden be destroyed.
The next morning, Lady Oonagh finds out that the children of Sevenwaters are trying to call the Lady of the Forest to their aid to fight against her. She arrives on the scene just after Sorcha has finished calling the Lady of the Forest. She casts Sorcha's brothers under a spell which turns them into swans; Sorcha escapes because of her brothers' quick warning. Realising that Sorcha can undo the spell and ruin her plans, Lady Oonagh searches for Sorcha to kill her, to no avail. Some months after the spell is cast, Lady Oonagh gives birth to Ciaran, who she plans to control Sevenwaters through when he becomes the chief. Lord Colum grieves for his children, to Lady Oonagh's annoyance, and wishes to see Sorcha most of all, she who is the exact image of her mother, whom he loved dearly. He tries to break free from Oonagh's enchantment, but is unable to.
Many months later, Lady Oonagh is at Eamonn's holding when she meets Richard of Northwoods, who is collaborating with Eamonn. He makes mention of a strange girl at Harrowfield who is weaving shirts of starwort who matches the description of Sorcha. The Lady Oonagh strikes a deal with him: kill Sorcha and destroy her weaving equipment and shirts, and Oonagh will give Richard land in Erin. Richard agrees to it, and returns to Briton.
Months later, Lady Oonagh hears about the breaking of the curse. Realizing she has lost, she escapes with Ciaran before the children of Sevenwaters return to apprehend her.
In 'Twixt Firelight and WaterEdit
Oonagh returns to her former home with Ciaran, and leaves him in the care of an elderly couple, paying them to take care of him until he is old enough to begin learning magic. She orders her elder son, Conri, to keep an eye on them, saying they would harbour ill will towards her. When Ciaran begins to show signs of power, Oonagh begins training him. Her methods are harsh, threatening to break her son's spirit.
Some time after she begins training Ciaran, Oonagh leaves on a journey. While she is absent, Lord Colum, Cormack and Diarmid come for Ciaran and Conri helps them get him safely away. When Oonagh returns and finds her "weapon" missing, she flies into a rage and turns on Conri, suspecting his involvement. She tortures him, but he refuses to give any information. When he at last predicts that Ciaran will defeat her, she unleashes her full wrath and places him under a geis. He will remain in the form of a raven for fifteen years, but should someone recognise him, he will be trapped in that form unless a woman of the Sevenwaters family agrees to marry him. She believes none would ever agree to such a condition, and later gloats to Ciaran about this act, thinking herself ingenious.
In Son of the ShadowsEdit
The Lady Oonagh is not present in the novel, but when Ciaran and Niamh are revealed to be in a relationship it is thought that she has had a hand in it. After finding out his true heritage from Conor, Ciaran seeks his mother out so that he can learn how to control his magic. Oonagh tries to use him as a pawn against Sevenwaters, but Ciaran is stronger than she thinks.
Ciaran moves to Kerry with Niamh, his beloved, and they have a child, Fainne. The Lady Oonagh visits them from time to time, and causes the death of Niamh by pushing her off the Honeycomb.
In Child of the ProphecyEdit
It is sixteen years later, and Ciaran lives with Fainne in Kerry, and receives some visits from the Lady Oonagh. Ciaran invites Oonagh to Kerry to teach Fainne the ways of living with a household like Sevenwaters, for he intends for Fainne to meet her mother's family and live with them at Sevenwaters. However, the Lady Oonagh has other plans. She blackmails Fainne into becoming her spy and minion by threatening to kill Ciaran. She claims that she has put Ciaran under a spell that has made him ill, and that she can kill him if Fainne refuses to do what Oonagh wants her to do (whether Ciaran actually was under a spell or the Lady Oonagh was lying about it is unknown). She gives Fainne a necklace which she uses to control Fainne.
During Fainne's stay at Sevenwaters, the Lady Oonagh forces her to do terrible things, including setting fire to a building and seriously injuring Maeve, the daughter of Lord Sean. Oonagh also harms people that Fainne becomes close to, such as Coll (Liadan's son). Oonagh is afraid of what Fainne will do without the necklace to control her, and when she tries to take it off goes to her and forces her to put it back on.
During the final battle for the Islands, Oonagh appears and causes chaos. She forces Fainne to come out of hiding. She expects Fainne to side with her, but Fainne fights against her. Much to the Lady Oonagh's surprise, Ciaran arrives to fight against Oonagh. After a brief conversation, in which she admits her guilt in Niamh's death, Oonagh attacks Ciaran with a fireball; Finbar throws himself in its path and saves Ciaran's life, and sacrificing his own. Oonagh tells the army gathered there the true task the Child of the Prophecy must undertake, and believes that she has won, because their Chosen One is a warrior and leader, and unable to stand watch at the Needle. However, Ciaran reveals that the true Child of the Prophecy is Fainne, who is perfect for the role, having been raised in a druidic lifestyle and bears the mark of the raven on her shoulder. The Fair Folk and the Old Ones appear to take Fainne to the Needle. Fainne turns her into a mouse, claiming she can take her chances like the rest of them have to, and is eaten by one of the Fomhoire, who has taken the form of an owl.