During the events of Camelot: Season 1 Episode 4 Lady of the Lake played by Sinead Cusack
When Morgan and Vivian arrive at the castle, Sybil is waiting inside. Morgan orders Sybil taken out of the castle and she is thrown outside. After she starts to bleed from her eyes, Morgan has Vivian bring Sybil into the castle. Sybil asks Morgan what her symptoms are and asks her if she performed a summoning and accuses her of being reckless. She puts Morgan into a protective circle and Morgan hears Uther and King Lot taunting her and she loses consciousness. Sybil sees the Scullery Girl and then Queen Igraine and Morgan suddenly regains consciousness. She starts to writhe and her appearance changes to that of Igraine. Later, Sybil tells Morgan that the nunnery burned down and she was the only survivor.
During the events of Camelot: Season 1 Episode 5 Justice played by Sinead Cusack
Sybil walks to Morgan and tells her that she needs allies and friends from the influential people of Britain. She continues that Morgan must tell people that she will take away their fears and then she will have their loyalty. Morgan has a meeting with influential members of Britain and tells them that any fears they have can be shared with her. Ernald stands up and tells her that they all rejoice in King Arthur's rule. Sybil goes to a bar and sits down next to Tomal. She asks him if he is a mercenary and then offers him money for him to beat her. Vivian carries Sybil into Morgan's castle and Sybil reveals to Morgan that her beating was all part of her plan and to use it to her advantage. Later, Tomal sees Sybil and realizes she works with Morgan. Sybil tells Morgan about Tomal being at the dinner. Morgan tells Tomal to come to her and asks Sybil if he is the one that hurt her and before Tomal can say anything, Morgan slits his throat.
During the events of Camelot: Season 1 Episode 6 Three Journeys played by Sinead Cusack
The first group of the day to ask Morgan's judgement is Warin, Mary's Son, and Mary. Mary tells Morgan that she and Warin haven't been together for seven years and now he wants Mary's Son to help him with his farm. Warin thinks he should have Mary's Son, because he is old enough to work and is the only family he has. Morgan offers to buy Mary's Son and after Warin tries to haggle with her, Morgan gives Mary's Son to Mary.
Sybil is telling Morgan what a good job she did and she should use her powers. Vivian walks in and tells Morgan that Arwen said she was in danger. Morgan walks into the main hall with Vivian and Sybil and Arwen accuses Sybil of being a devil. Arwen uncovers her face and reveals her burn scars. She says that her daughter was in the nunnery when Sybil set it on fire. Arwen tells Morgan that she wants justice and Sybil must be executed. During the hearing, Sybil asks for forgiveness and says every year there was a ritual and in order to hide it from the priests, she set the nunnery on fire. Sybil tells Morgan not to let Arwen's accusations take them off course. Morgan gives her verdict and places Sybil's hand in the fire. Arwen wants more, but is told to leave. Morgan afterwards treats Sybil's burnt hand.
During the events of Camelot: Season 1 Episode 7 The Long Night played by Sinead Cusack
Morgan brings Harwel to the dining area and has him tell Sybil his name and that he will do anything for her. Morgan then tells Vivian to get him prepared. Morgan asks Sybil if everything is prepared and tells her that Arthur will come for the feast. During the feast Arthur's men get drunk and Morgan offers her love and devotion to Arthur.
Dancers start dancing in front of the group and at the end of the dance stick swords in front of the diners. After dinner, Morgan tells Sybil to give the signal. Gawain goes back to watch over Arthur and the castle suddenly is attacked by flaming arrows. Everyone gathers for a meeting and Morgan wonders who is attacking her and Merlin thinks Aldwulf, a warrior king from the east might be behind the attack. Merlin questions Sybil about why she is at the castle.
As they sit in a circle, Sybil tells Morgan that Leontes loves Guinevere more than life itself and Morgan says that Camelot rests on Arthur's honor. Vivian tells them that they all confide in Igraine. In the morning, Morgan's Captain returns and says that they defeated Aldwulf's men. Sybil tells Harwel to recruit some men to attack the outpost at Bardon Pass. Arthur and the others ride back to Camelot and Sybil brings food to a chained up Igraine, revealing the one riding with Arthur is really Morgan.
During the events of Camelot: Season 1 Episode 8 Igraine played by Sinead Cusack
Igraine is forcibly cleaned by Sybil. Sybil chains Igraine up and then locks the door. Sybil asks Vivian how absolute her loyalty is to Morgan and then tells her that Morgan asked that she follow Sybil's requests without question. She tells her that Morgan is at Camelot and then shows her Igraine chained up. Igraine asks Vivian to help her, but Vivian walks away. Sybil tells Igraine that her own decisions have brought her to her current state. She calls Igraine a whore who sired a bastard and Igraine grabs Sybil with the chains and starts to choke her. Sybil calls for help and Donal threatens to kill Igraine if she doesn't release Sybil. Sybil is released and she tells Donal not to talk to Igraine.
During the events of Camelot: Season 1 Episode 9 The Battle of Bardon Pass played by Sinead Cusack
Morgan returns to her castle and tells Sybil that she was successful in her mission and everyone will think Igraine has gone mad. Sybil introduces Morgan to a group of mercenaries including Mercenary 1, and Mercenary 2. Mercenary 1 says he doesn't owe Arthur anything and Morgan tells them that she wants to strike at different locations to show how fragile Arthur's protection is. Mercenary 2 says he will attack anywhere for a price, and she offers them leadership roles if she wins the crown.
Vivian asks Sybil how they will avoid punishment for kidnapping Igraine and Sybil tells her to give her total loyalty to Morgan. Acton tells Morgan that the trade routes are unsafe and Alric says that the banner of Arthur means nothing. Morgan acts like she is still loyal to Arthur and she blames Merlin for leading Arthur astray.
Merlin and Igraine ride into Morgan's castle and when Morgan comes out, Merlin accuses her of numerous charges. Injured Woman says that Morgan is the only one they can trust and Morgan and Sybil take Igraine and Merlin to where Igraine says she was tortured, but the room has been transformed into a prayer room. Merlin tells Morgan that she is under arrest and instead Merlin and Igraine are arrested. Merlin and Igraine are bound with ropes and dragged behind Morgan and Sybil as they ride to Camelot. Morgan and the others stop at Borin's pub and he tells them that the people gathered there are all afraid of attacks on their home.
During the events of Camelot: Season 1 Episode 10 Reckoning played by Sinead Cusack
Morgan arrives at Camelot with her entourage and Bridget tells her that Arthur is at Bardon Pass repelling an attack. A Camelot guard sees Igraine tied up and goes to untie her, but is stopped by a Pendragon guard and Sybil tells the crowd that Merlin and Igraine ransacked Castle Pendragon and threatened Morgan. Borin asks Morgan where Arthur is and that he heard rumors that Arthur fled with Guinevere. Sybil knocks on the door where Morgan is and Fourth Marauder hands her Arthur's sword. Sybil taunts Merlin and then has him released from the pillory so he can watch as Morgan presents Arthur's sword to the crowd. Borin asks who will be the new ruler and Sybil nominates Morgan and she accepts.
Morgan is about to be crowned queen when Arthur walks into the throne room. Morgan runs to him as if she is happy to see him, but Arthur chastises the people for so quickly crowning a new leader and Merlin is released. Borin asks where Arthur was and Arthur tells Morgan to give him back his sword and crown. Morgan says he has lost the will of the people, but Brastias takes Arthur's sword from Vivian and the crown from Sybil. Gawain and Kay drag Wallace into the throne room and Wallace tells the crowd of Morgan's plan. Sybil tells everyone that she planned everything and Morgan knew of nothing. Gawain takes Sybil to her execution spot and before Gawain cuts off her head, Merlin tells her that there is no god.