Cersei serves as one of the two main antagonists of Season 1 (alongside Jaime Lannister), a secondary antagonist in later seasons, until she climatically steps up as one of the two main antagonists of Season 7 (alongside the Night King).
In the TV series, she is portrayed by Lena Headey, who also notably portrayed Madeline Madrigal in Dredd.
Season 1 Edit
Robert, Cersei, and most of the court visit the North to appoint Eddard Stark as Hand of the King. During the royal visit to Winterfell, Eddard's son Bran finds Cersei and Jaime committing incest in a tower. To prevent their adultery and incest from being revealed, Jaime pushes Bran from the tower. Bran survives, but has no memory of the fall and is left paraplegic. Cersei learns that her husband Robert is in danger of finding out that the children he sees as his heirs to the throne are not his.Robert meets his end as the result of a boar attack on a hunting trip, before Ned Stark tells him the truth about his children. Cersei works quickly to instate her oldest son, Joffrey, on the throne, with her as his chief political advisor and Queen Regent. Joffrey, however, quickly shows signs of independence. Eddard eventually discovers the truth of Cersei's infidelity and confronts her, giving her the opportunity to flee into exile and thus spare her children certain execution. Cersei had already arranged Robert's death in a hunting "accident"; when he dies, Cersei seizes control as regent and has Eddard arrested for treason. Cersei intends for Eddard to publicly confess and join the Night's Watch as punishment, but instead Joffrey orders Ned executed.
Season 2 EditFrustrated with Cersei's many political blunders as well as her failure to control Joffrey, Tywin appoints Tyrion Hand of the King, with explicit instructions to control Cersei and Joffrey. Once at the capital, Tyrion enters into a bitter power struggle with Cersei, subverting her authority and removing her supporters from positions of power.
Tywin decides that Cersei does not exercise enough control over her son and sends Tyrion as an additional political advisor. Cersei and Tyrion do not get along, and constantly try to undermine each other's authority over the crown. In Jaime's absence, Cersei takes their cousin Lancel Lannister as her lover, an affair that Tyrion discovers. Ultimately, Tywin and the Tyrell armies arrive in time to force Stannis to retreat and save the city. As of the end of season 2, Tyrion has accumulated more sway over the Iron Throne, has shipped Cersei's only daughter off against Cersei's will to be married to the Prince of Dorne, and is forcing their cousin Lancel, with whom Cersei is having an affair, to inform on her. When Stannis Baratheon sails on King's Landing, Cersei and Joffrey stay enclosed in the Red Keep, leaving Tyrion to mastermind the defense of the city. Tywin's arrival with the Tyrell army robs both siblings of their influence at the last possible moment.
Season 3 EditAfter formally assuming his position as Hand of the King, Tywin makes it clear to Cersei that she is no longer welcome at Small Council meetings, de facto stripping her of political authority. Furthermore, Tywin intends to wed Cersei to Wilas Tyrell in order to form an alliance with House Tyrell. Cersei comes to fear that Margaery Tyrell intends to usurp her as queen and unsuccessfully tries to alienate Joffrey from her. Cersei is delighted when Tywin learns of the Tyrells' plan to wed Sansa Stark to Margaery's brother Loras, and he intervenes by having Tyrion marry Sansa instead, but is furious when Tywin also orders Cersei to marry Loras. When Jaime returns to King's Landing, he immediately seeks out Cersei, who is shocked to discover that his sword hand has been cut off.
Season 4 EditCersei has Tyrion arrested after Joffrey is fatally poisoned. Mourning and vindictive, it's implied that guilty or innocent, she wants Tyrion dead, while Jaime refuses to believe Tyrion is capable of familial regicide.Indeed, at Tyrion's trial, it is apparent Cersei has manipulated the proceedings so that the witnesses give either incomplete or entirely false testimonies to implicate Tyrion and Sansa further in the murder. When Tyrion demands a trial by combat, Cersei chooses Ser Gregor "The Mountain" Clegane as royal champion, to further diminish Tyrion's chances, and bribes Bronn via betrothal to a noblewoman, to secure his veto as Tyrion's champion. Cersei's wish comes true when Tyrion's champion, Oberyn Martell, is killed by Clegane. She still refuses to marry Loras, threatening even to reveal the truth of her incestuous relationship with Jaime and their three blond children. Tywin is killed by an escaping Tyrion soon afterward. Tywin then pronounces Tyrion guilty and sentences him to death, but Tyrion escapes prison and kills Tywin. Cersei is once again in complete control of the capital.
Season 5 EditWith the deaths of her father and elder son, Cersei de facto rules the kingdom. Her youngest child, Tommen Baratheon, is crowned king but is widely considered weak, signing every decree that passes in front of him. He is leading a kingdom on the brink of ruin: the huge losses suffered by House Lannister in the war, combined with the wartime disruptions to trade and harvest, render the Lannisters dependent on resources from House Tyrell. The Tyrells leverage this position and begin to build power in the capital, much to Cersei's consternation. Cersei receives a threat from Dorne, where Myrcella is betrothed to Trystane Martell, and sends Jaime to Dorne to retrieve her. Tommen is married to Margaery, who tries to manipulate Tommen into sending Cersei to Casterly Rock. Fearful of losing her power, Cersei meets the religious leader, the High Sparrow, appoints him as the High Septon, and gives him authority to re-establish the Faith Militant. In order to destabilise House Tyrell, Cersei arranges for the High Sparrow to arrest Loras for his homosexuality, and have Margaery also arrested for perjury after lying to defend Loras. However, Cersei's plot backfires when Lancel, now a member of the Faith Militant, confesses to his affair with Cersei and his role in Robert's assassination, and accuses Cersei of incest, prompting the High Sparrow to arrest her. Cersei is eventually allowed to return to the Red Keep after confessing to having committed adultery with Lancel, but has her hair cut off and is forced to walk naked through the streets of King's Landing as atonement. Cersei returns, distraught from the abuse directed at her by the smallfolk of King's Landing, but is consoled by Qyburn's successful reanimation of Ser Gregor Clegane.
Season 6 EditCersei remains in the Red Keep, confined to her chambers and stripped of her authority. Although she accepts Tommen's apology for his lack of action in her arrest and walk of atonement, she remains looked down upon by other members of the court. Cersei learns from Tommen that the High Sparrow plans to have Margaery do a walk of atonement before Cersei's trial and conspires with the Small Council to have the Tyrell army march on the Sept of Baelor to secure Margaery's and Loras' release. Their plan backfires when it is revealed that Margaery has joined the Faith of the Seven and has convinced Tommen to merge the Faith and the Crown. Despite being stripped of her allies, Cersei opts to remain in King's Landing, having named Ser Gregor as her champion in her trial by combat. However, Tommen announces that trial by combat has been abolished and replaced by trial by the Seven. Cersei arranges for a cache of wildfire to be detonated beneath the Sept during Loras' trial, which kills the High Sparrow, Margaery, Loras, and the rest of the Small Council. As a result of Cersei's actions, Tommen commits suicide. In the power vacuum following Tommen's death, Cersei claims the Iron Throne as the first ever Queen Regnant of the Seven Kingdoms.
Season 7 EditDespite nominally being ruler of Westeros, Cersei's grip on the throne is tenuous, with the Riverlands in upheaval following Arya Stark's massacre of House Frey, the Vale and the North's declaration of Ned Stark's bastard son Jon Snow King in the North, and Tyrion, Yara Greyjoy, Dorne, and the Reach all supporting Daenerys Targaryen, whose fleet has seized Dragonstone. Cersei remains cold and distant after Tommen's suicide, viewing it as a betrayal of their family. With no children left to protect, Cersei's malice and vindictiveness have grown, and she relentlessly seeks to expand her power and destroy her enemies. Cersei reaches out to the King of the Iron Islands, Euron Greyjoy, to form an alliance, but rejects Euron's marriage proposal as she considers him untrustworthy. Euron later ambushes Daenerys' fleet and captures Yara Greyjoy, Ellaria, and Tyene Sand, and presents them as a "gift" to Cersei. She agrees to marry Euron after the war is won; however, she continues her affair with Jaime, no longer attempting to hide their relationship from their servants. Cersei imprisons Ellaria and Tyene in the dungeons, kills Tyene with the same poison used to kill Myrcella, and keeps Ellaria alive to watch her daughter die.
Tycho Nestoris of the Iron Bank arrives in King's Landing to request repayment of their debt. Cersei requests a fortnight in order to comply. She then has the Lannister and Tarly armies attack Highgarden, defeating the Tyrells. Olenna Tyrell commits suicide following the defeat and gloats to Jaime that she was responsible for poisoning Joffrey. The Tyrells' wealth is transported safely to King's Landing, but the food the Lannisters steal from the Reach is destroyed when Daenerys attacks the caravan with her Dothraki horde and dragon, Drogon. Jaime barely survives the battle and encourages Cersei to consider a ceasefire. Tyrion infiltrates the capital to meet with Jaime, and Jaime tells Cersei that Daenerys and Jon want to meet with Cersei to negotiate an armistice while mankind fights the threat of the White Walkers. Cersei is skeptical but agrees, and tells Jaime that she is pregnant. Daenerys and Jon meet with Cersei in the Dragonpit on the outskirts of King's Landing, and present to her a wight captured from the White Walkers as evidence of their threat. Although terrified, Cersei initially refuses to agree to an armistice, as Jon refuses to remain neutral in the war between the Lannisters and Targaryens. Tyrion speaks to Cersei in private, and apparently persuades her to ally with the rival monarchs. However, she later reveals to Jaime that she intends for her enemies to wipe each other out and then attack the victor, and has sent Euron to Essos to transport the Golden Company to Westeros. Disgusted by Cersei's selfishness and shortsightedness, Jaime finally abandons her side and goes north on his own, leaving Cersei alone.
Season 8 EditCersei is informed that the White Walkers have breached the Wall, to her delight. Euron Greyjoy returns to King's Landing with the Golden Company, and Cersei finally has sex with him. Cersei tasks Qyburn with hiring Bronn to kill Jaime and Tyrion, using the crossbow with which Tyrion had killed Tywin.
Cersei permits civilians to seek refuge in the Red Keep – ostensibly to protect them from an invasion of King's Landing, but in reality she plans to use them as human shields to deter an attack. The Iron Fleet kills one of Daenerys' dragons, Rhaegal, and takes her advisor Missandei captive. When Euron returns to King's Landing, Cersei reveals that she is pregnant and lies that it is his. Daenerys, Tyrion, and her other advisors travel to King's Landing demanding Cersei's surrender, but Cersei is unmoved and has the Mountain behead Missandei in front of Daenerys. Daenerys subsequently launches an attack on the Iron Fleet, the Red Keep, and the anti-dragon defenses Cersei has had installed on King's Landing's walls, but then continues to burn the rest of the city. Cersei attempts to take shelter and is found by Jaime, who had infiltrated the Red Keep on Tyrion's orders to evacuate her. However, their passage is blocked by rubble. The Red Keep begins to collapse, and Jaime comforts Cersei in their final moments as they are crushed by falling debris. Their bodies are later found by Tyrion, whose subsequent grief leads him to renounce his loyalty to Daenerys and persuade Jon Snow to kill her.