Cersei Lannister, played by Lena Heady, is the daughter of Tywin Lannister, the twin sister of Jaime Lannister, and the older sister of Tyrion Lannster. Cersei loves her brother Jaime and despises her brother Tyrion.

Early Life and Marriage

Cersei Lannister was raised at Casterly Rock, the seat of power for House Lannister. Her mother died when Cersei was just four years old while giving birth to Tyrion. With her mother gone, and her father frequently away in King's Landing serving as Hand of the King, Cersei began to rely more and more on her brother Jaime, and the two began a secret, incestuous relationship that would continue for the rest of their lives.

As a child, Cersei visited a purported witch named Maggy,who lived in the forest next to Casterly Rock. There, Cersei received an ominous prophecy that would haunt cast a shadow over her for decades to come, foretelling that she would marry a king, but would lose all of her children, before being overthrown by a younger queen.

In her youth, Cersei was regarded as an incredible beauty, and her father Tywin sought out a marriage for her that would increase his family's prestige. He originally hoped that she could marry into the royal family, and asked the mad king, Aerys II Targaryen, to agree to a union between Cersei and the heir apparent Prince Rhaegar Targaryen. Aerys cruelly spurned this proposal, believing that House Lannister was too far beneath him, a decision that would in part lead to Tywin's vicious betrayal of Aerys during Robert's Rebellion.

During this conflict, Tywin sacked King's Landing, and his own son was the one to end the mad king's life, endearing himself to the new king, Robert Baratheon. Following the end of this war, Tywin was successful in arranging a marriage between Cersei and Robert, making Cersei the Queen of Westeros.

Cersei and Robert's marriage was loveless though, and she maintained her secret relationship with her twin brother Jaime, who ultimately became the father of all three of her children. Robert for his part fathered over a dozen bastard children outside of his marriage as well.

Journey to Winterfell

After the mysterious and sudden death of the Hand of the King, Jon Arryn, Cersei and her brother Jaime accompany King Robert north to Winterfell, where Robert plans to name Eddard Stark as the new Hand.

While climbing a tower in the castle, Bran Stark encounters Cersei and Jaime having sex. When the couple sees him, Jaime pushes him from the tower in order to keep their secret. Bran survives the fall, but is permanently crippled, and falls into a coma.

Soon after, an assassin comes for Bran, but is unsuccessful. A dagger used in the attempt is eventually traced back to Tyrion Lannister. Furthermore, Catelyn Stark discovers blonde hair in the tower he fell from, causing her to suspect that one or more of the Lannisters were involved.

Cersei returns with the royal caravan to King's Landing, and on the road, her son Joffrey is involved in an altercation involving Arya Stark, her pet direwolf, and a butcher's boy named Mycah. As retribution, Cersei orders that one of the Starks' direwolfs be killed, which Robert complies with.

Return to King's Landing

Returning to King's Landing, tensions with House Stark have been exacerbated significantly. Eddard Stark has begun to investigate Jon Arryn's death, and not long after, news arrives that Catelyn Stark has taken Tyrion prisoner in the Riverlands. Jaime Lannister instigates a fight with Eddard in retaliation, nearly killing him.

Eddard confronts Cersei, revealing that he knows the true lineage of her children, and will tell Robert, who is currently away on a hunting trip. Aware of this plot though, Cersei had previously orchestrated the death of her husband, using Robert's Lannister squire to keep him drunk, and resulting in a mortal injury while hunting a boar. Robert returns to King's Landing, but dies soon after from his wounds, and never learns the parentage of his three presumed children.

With the help of allies in King's Landing, Cersei secures the throne for her son Joffrey, and has Eddard arrested as a traitor, and his claims discredited. She further manages to convince Eddard to falsely admit to treason, with the assumption that he will be allowed to join the Night's Watch in exile, and his two daughters in King's Landing will not be harmed.

This plan goes awry though when Cersei's son Joffrey, now the anointed king, orders Eddard's execution at the Sept of Baelor. The northern houses led by House Stark, and joined by the the families loyal to House Tully, declare open rebellion. In the opening skirmishes of this war, Jaime Lannister is captured by Stark forces.

The War of the Five Kings

With House Stark and House Lannister in open war, the fighting threatens to intensify, with both of Robert's brothers separately declaring their own claims to the throne, having gotten word of [Eddard Stark]]'s allegations of Joffrey's illegitimacy. To the west, Balon Greyjoy of the Iron Islands declares his own rebellion, adding a fifth faction to the conflict.

With Tywin Lannister away fighting this war, Cersei strengthens her position as the de facto ruler of Iron Throne, serving as Queen Regent to Joffrey. However, untrusting of his daughter, Tywin dispatches Tyrion to King's Landing to act as the Hand of the King, and to keep Cersei in check.

The two almost immediately find themselves in conflict, with Cersei working to undermine Tyrion's authority, and Tyrion trying to reign in the more destructive impulses of Cersei and Joffrey.

After the assassination of Renly Baratheon, Tyrion correctly predicts that Stannis Baratheon will now turn his attention to an attack on King's Landing. With Tywin's army occupied by the Stark forces, Cersei and Tyrion busy themselves with preparing for the city's defense.

Stannis's fleet attacks King's Landing in what will later be known as the Battle of Blackwater, and Cersei orchestrates an attack on Tyrion Lannister during the battle, hoping to rid herself of her troublesome brother one and for all. The initial defense does not go as well as hoped however, and Cersei prepares for the worst by getting ready to poison herself and her children.

Just as Stannis is preparing to breach the city, he is routed by Tywin, who has managed to return, leading an alliance between House Lannister and House Tyrell. In the aftermath of the battle, Tywin is named as the new Hand of the King, and Joffrey is betrothed to Margaery Tyrell.

Power Struggle in King's Landing

As the war in the Riverlands continues, Cersei finds that she has a new rival in King's Landing, as the king's new bride and her family begin to establish their own hold over the capitol. This is exacerbated for Cersei when Tywin reveals to her his plan to marry her to Loras Tyrell, to further strength the bond between the Lannisters and Tyrells. Cersei refuses, knowing it will all but eliminate her influence over Joffrey and the Iron Throne.

The leaders of the Stark rebellion are killed in an assassination at the Red Wedding, and with Stannis Baratheon crippled by his losses at Blackwater Bay, and the Ironborn contained in the north, the War of the Five Kings is all but over. Jaime returns to King's Landing, and Cersei sees that he has lost his hand during the war.

The Purple Wedding

Shortly after the end of the war, Joffrey's wedding to Margaery is set. At the proceedings, Joffrey is killed by poison, and Cersei immediately lays blame on Tyrion and has him arrested.

Joffrey's younger brother Tommen is crowned king, and a trial is set to determine Tyrion's guilt or innocence. Tyrion requests a trial by combat, a strategy that Cersei tries to foil by bribing away Bronn, Tyrion's personal guard, and by electing Ser Gregor Clegane as the champion fighting for Tyrion's guilt.

In Bronn's place, Tyrion elects Oberyn Martell to be his champion. Despite initially seeming to be victorious, Oberyn is killed. Tywin sentences Tyrion to death, pleasing Cersei

Meanwhile, Cersei attempts to put an end to Tywin's plan to marry her off once and for all, revealing to his face that she did and continues to have an incestuous relationship with her brother. She begins to surround herself with potential allies, including the disgraced maester Qyburn.

The Death of Tywin

While awaiting his execution, Tyrion is freed by his brother Jaime, and escapes. Before he leaves the city however, he encounters his father, and kills him.

With Tywin dead, Cersei returns her attention to expanding her influence in King's Landing, and contending with the ambitions of House Tyrell. To do so, she empowers a religious figure called the High Sparrow, naming him High Septon, and giving him the authority to reinstate the Faith Militant, a military arm of the church that was abolished over 200 years ago.

The church subsequently arrests Loras Tyrell, and later her sister Margaery, giving Cersei an opportunity to disrupt their family's growing influence over King Tommen.

Cersei's plan backfires though when the Faith Militant arrest her as well on the accusation of incest. To escape her imprisonment, Cersei admits to having an incestuous relationship with Lancel Lannister, but hides her one with Jaime. As punishment, she is forced to walk the streets of King's Landing naked, enduring the jeers and insults of the gathered crowd. Arriving at the Red Keep, Qyburn reveals to Cersei that a secret project commissioned by her is complete: a monstrous warrior created from the reanimated remains of Ser Gregor Clegane.

Eliminating Her Enemies

After her walk of shame, Cersei struggles to maintain her power in King's Landing. Her daughter, Mrcella, is killed by an assassin while leaving Dorne, and Cersei finds that she is being barred from leaving the Red Keep. Furthermore, Cersei is removed from the Small Council.

As Cersei's power slips, she receives an order from the High Septon to return to the Sept of Baelor, which she refuses by having one of the Faith Militant killed. She nevertheless finds out that the church has manipulated her son into barring a trial by combat, foiling Cersei's plans.

Backed into a corner, Cersei enacts a plan to kill all of her enemies in one fell swoop. At the date of her trial, Cersei doesn't attend. Instead, she has a huge cache of wildfire buried beneath the Sept of Baelor ignited, incinerating the temple and everyone inside, including the High Septon, Margaery Tyrell, Loras Tyrell, Mace Tyrell, and Kevan Lannister. Witnessing what had just happened though, Tommen, Cersei's last surviving child, commits suicide.

Queen of the Seven Kingdoms

Despite the loss of all of her children, Cersei moves to fill the power vacuum left in the wake of the destruction. She declares herself Queen, and without any true rivals in King's Landing, is unopposed. Ruling under the Lannister name instead of Baratheon, Cersei effectively starts a new royal dynasty.

With a massive army led by Daenerys Targaryen making landfall on Dragonstone, Cersei acts quickly to secure allies. She brokers a truce with Euron Greyjoy of the Iron Islands to add the Iron Fleet to her forces, and convinces House Tarly to abandon their former loyalty to House Tyrell and join with her.

Cersei wins early victories in her war with Daenerys, defeating her allies at sea, and luring her army to Casterly Rock in order to sack Highgarden, eliminating House Tyrell.

She is soon handed a huge defeat however, when Daenerys unleashes her dragon on the Lannister army, killing thousands, including Randyll Tarly and his heir, Dickon Tarly. Cersei plans to hire a new army formed with mercenaries, using funds provided by a loan provided by the Iron Bank.

The Dragonpit

At the behest of her brother, Cersei later agrees to meet with Daenerys Targaryen and her allies at the Dragonpit in King's Landing.

After witnessing a wight first-hand, Cersei is initially amicable to a temporary truce, but demands that Jon Snow maintain the northern kingdom's neutrality during this armistice. Jon refuses, and Cersei leaves the negotiations.

She later meets with Tyrion, and tricks him and his allies into believing that she will march the Lannister armies north to their aid. Instead, Cersei plans to allow the northerners and Targaryen forces to fight the army of the dead alone. At the same time, she she dispatches the Iron Fleet to Essos, in order to ferry back a mercenary army called the Golden Company to bolster her own forces.

At this betrayal, Jaime Lannister decides to abandon her, and despite her initial threats, she is unable to order his execution and allows him to leave.