Lannicest

Lannicest is the family/het ship between Cersei and Jaime Lannister from the Game of Thrones fandom.

In the books
As children, Cersei and Jaime were inseparable. They looked so alike that Cersei would sometimes dress as Jaime and take his lessons in swordfighting. They started sexually experimenting when they were very young, and were once caught by a servant, who informed their mother, and were made to sleep on separate sides of their castle, Casterly Rock.

At the age of twelve, their father Tywin brought Cersei to court in King's Landing as the daughter of the Hand of the King, while Jaime became a squire to old Lord Crakehall. The twins were mostly apart for three years until Jaime came to King's Landing to be knighted. Cersei informed him that Tywin planned to marry Jaime to Lysa Tully, and seduced him in order to convince him to join the Kingsguard. As a Kingsguard knight, he could not marry another woman, and Cersei hoped that they would be together at court as Kingsguard and Hand's Daughter. Although Cersei managed to land Jaime a place on the Kingsguard, Tywin was infuriated by the king disinheriting his son and resigned, moving Cersei back to Casterly Rock.

After King Aerys II was overthrown, Cersei was arranged to be married to the new king, Robert Baratheon. As queen and knight of the Kingsguard, Cersei and Jaime were together once more, and they slept together on the morning of Cersei's wedding. Over the next fourteen years, she and Jaime had three children, which she passed off as Robert's. Cersei liked to believe that their eldest son Joffrey was conceived during a royal visit to the island of Greenstone.

Eventually, the new Hand of the King, Jon Arryn, and King Robert's brother, Lord Stannis, grow suspicious of the paternity of Cersei's children, which starts the events of the main series. After Jon Arryn is poisoned by his wife, Cersei and Jaime join the king in going to Winterfell, where Ned Stark is named Hand of the King. At Winterfell, Cersei and Jaime have sex in an abandoned tower, and are caught by Ned's second son Bran. Desperate to keep their secret affair safe, Jaime pushes Bran from the tower "for love," leaving him disabled.

Cersei and Jaime return to the capital and are separated for the next few books after Jaime leaves the city after hearing about Catelyn Stark's arrest of their brother Tyrion. During their time apart, King Robert is killed by Cersei to avoid suspicion and their son Joffrey becomes king. They are reunited at Joffrey's funeral after he is poisoned at his own wedding, and proceed to have sex in the sept before their son's corpse. He proposes that they announce their incest to the world and marry as the Targaryen monarchs had done before them, but Cersei refuses, knowing it would mean the deaths of them and their children.

When Jaime helps Tyrion escape from the dungeons, doubt is planted in Jaime's mind about Cersei's fidelity, as Tyrion claims that Cersei has been sleeping with other men. This haunts Jaime for the events of the next novel. Tywin's murder at the hands of Tyrion make Cersei increasingly paranoid, and she burns the Tower of the Hand in an attempt to see if Tyrion is hiding in the castle. Jaime is increasingly repulsed by her mental decay. Jaime and Cersei are parted once more when he goes to the riverlands to make the Tullys and Blackwoods surrender. At court, Cersei sleeps with other people, mostly for political gain. After she is imprisoned, she sends a letter to Jaime, asking him to rescue her, but he orders it be burnt.

In the show
The relationship differs following the death of Joffrey. Cersei is willing to expose the relationship to gain leverage of Tywin, and she professes her love to Jaime much more strongly, including sleeping with him once more in White Sword Tower in the Season 4 finale. Instead of immediately going to the riverlands, Jaime is sent to Dorne to rescue Myrcella from Ellaria Sand's threats. Myrcella dies, and the siblings mourn their daughter upon Jaime's return to King's Landing.

Jaime is eventually sent to the riverlands and returns to find that their last son Tommen is dead and Cersei is queen in her own right of the Seven Kingdoms, having killed all of her opposition. Jaime supports Cersei in her campaign against Daenerys Targaryen after she lands off the coast of Westeros, and they conceive another child. However, Jaime abandons Cersei after learning that she intends to give no help to Daenerys and Jon Snow in the war against the White Walkers, believing that the dead and her living opponents will finish each other off in the north.

Cersei commits further to marrying King Euron Greyjoy for an alliance with the Iron Islands, while Jaime has a fling with Brienne of Tarth. However, after the Battle of Ice and Fire, Jaime leaves Brienne and returns to Cersei's side after learning that Cersei is being attacked by Daenerys and Jon's armies. Jaime is mortally wounded by Euron while trying to reach Cersei. They retreat to the crypts and profess their love for one another, Cersei crying that her baby will die. They are both killed by the collapsing keep as Daenerys burns the city.

Joffrey Baratheon
Joffrey is the eldest son of Cersei and Jaime, and is believed to be the son of Cersei with King Robert. He is Cersei's favourite child, and is a very cruel individual. His dubious paternity and succession to the throne starts the war that becomes the main focus of the novels. Joffrey is poisoned by Olenna Tyrell and Petyr Baelish at his own wedding to Margaery Tyrell. Cersei and Jaime grieve his death and meet again for the first time since the first novel before his corpse.

Myrcella Baratheon
Myrcella is their second child and only daughter, also believed to be Robert's. She is more pleasant than Joffrey and more intelligent than Tommen. She is sent away to Dorne to be betrothed to Prince Trystane Martell to forge an alliance between the Iron Throne and Dorne. In the novels, Princess Arianne Martell unsuccessfully tries to name Myrcella queen, but the child is injured, but Prince Doran sends Myrcella back to King's Landing with Nymeria Sand. In the TV series, she is poisoned by Ellaria Sand.

Tommen Baratheon
Tommen is their third and youngest child. He is pleasant, and given his young age, he has little to do or say. After Joffrey's death, Tommen becomes King of the Seven Kingdoms and marries his brother's widow Margaery. Cersei is his regent in the books and tries to heavily influence him in the TV show. In the TV show, he commits suicide after Cersei blows up the Great Sept of Baelor with everyone inside, including Tommen's beloved wife Margaery.

Unborn child
This child only exists in the TV show, and was conceived after their other three children had died and Cersei was ruling queen of the Seven Kingdoms. Cersei dies while still pregnant with this child. Confusingly, Cersei's pregnancy never progresses, and she never appears pregnant, leading to some audiences believing she was faking her pregnancy. Although this is understandable, it doesn't appear to be the intention, as Cersei cries that she doesn't want her baby to die before she is killed. This appears to be a side effect of the known writing issues in the later seasons.

AU fanfiction or sequel fanfiction likes to imagine Cersei and Jaime having this child, either escaping Westeros or raising the child as their heir to the Seven Kingdoms. This child is often called Joanna or Tywin in fanfiction, after Cersei and Jaime's parents.

Fanon
Lannicest is a popular ship, yet controversial in the fandom due to its incestuous nature. It rivals the Braime ship, which pairs Jaime with Brienne of Tarth instead, along with rivalry with many fans who are against the ship due to the canon toxicity of the pairing and its incestuous nature. Some Lannicest shippers do not endorse the relationship as healthy, however, and are interested in the psyche that the relationship has on Jaime and Cersei as characters. Others do enjoy the relationship, and clarify that they only enjoy the fictional couple in Martin's world, and do not endorse real-world incest.

Fandom
FAN FICTION
 * (this tag is used for fics primarily about Cersei/Jaime, not setup for another ship or being a background ship)
 * Cersei/Jaime (TV) tag on FanFiction.Net
 * Cersei/Jaime (Books) tag on FanFiction.Net
 * Cersei/Jaime (Books) tag on FanFiction.Net