Ellaria Sand

"“A start? Gods forbid. I would it were a finish. Tywin Lannister is dead. So are Robert Baratheon, Amory Lorch, and now Gregor Clegane, all those who had a hand in murdering Elia and her children. Even Joffrey, who was not yet born when Elia died. I saw the boy perish with mine own eyes, clawing at his throat as he tried to draw a breath. Who else is there to kill? Do Myrcella and Tommen need to die so the shades of Rhaenys and Aegon can be at rest? Where does it end?”"

- Ellaria to the three eldest Sand Snakes "Oberyn wanted vengeance for Elia. Now the three of you want vengeance for him. I have four daughters, I remind you. Your sisters. My Elia is fourteen, almost a woman. Obella is twelve, on the brink of maidenhood. They worship you, as Dorea and Loreza worship them. If you should die, must El and Obella seek vengeance for you, then Dorea and Loree for them? Is that how it goes, round and round forever? I ask again, where does it end? I saw your father die. Here is his killer. Can I take a skull to bed with me, to give me comfort in the night? Will it make me laugh, write me songs, care for me when I am old and sick?"

- Ellaria to the three eldest Sand Snakes

Ellaria Sand is a major character in George Martin's A Song of Ice and Fire. She is the lover of Oberyn Martell. In the original novels, Ellaria Sand does not want revenge for Oberyn and only wants to protect her own young daughters. She is referred to as worshiping a Lysene love goddess, and she is sexually adventurous and potentially bisexual.

However, her personality has been drastically changed in the TV series, being not reasonable, hateful and bloodthirsty.

In the novels
After Oberyn's death, she returns with the Dornish party back to Dorne and brings her lover's remains back to Prince Doran. She wants to avoid a war against the Lannisters and is against harming Princess Myrcella. She is worried the cycle of revenge will continue until even her youngest daughters are eventually consumed by it. Doran and Ellaria don't trust Oberyn's eldest bastard daughters, Obara, Nymeria, and Tyene, who want revenge for their father's death by starting a war and burning Oldtown.

One of the Sand Snakes, Sarella Sand, is not in Dorne during the current story, but in Oldtown, disguised as a male maester apprentice named "Alleras".

It's the 3 eldest Sand Snakes who go against Doran's orders: Obara Sand, the most dangerous of the girls, approaches Prince Doran in the Water Gardens and accuses him of inaction and cowardice. Ellaria and Doran want the 3 Sand Snakes to stop their thirst for war, but they disobey and they are soon arrested by Areo Hotah, along with Oberyn's squire, Daemon Sand, and secluded in the Water Gardens with Ellaria and her natural daughters Elia, Obella, Dorea, and Loreza, to prevent them from being used by the plots of others. Meanwhile Doran and Areo return to Sunspear, the regional capital of Dorne, ruled by Doran's cousin Manfrey Martell. Sarella, remains free in Oldtown.

Queen Cersei is pleased to learn that the Sand Snakes are all imprisoned and her daughter Myrcella is safe in Sunspear. Doran plans to send her back to King's Landing, away from the Dornish people and Cersei plots to have killed the 11 years old Prince Trystane and blame Tyrion Lannister for his death. Meanwhile Doran's eldest son, Quentyn Martell, is secretely travelling to Meereen with his Dornish friends for a secret marriage with Daenerys Targaryen. In fact in the books Doran is supporting the Targaryens to take the Iron Throne.

At Sunspear, Princess Arianne Martell, Doran's daughter and eldest child, is plotting to take control of Dorne and crown Princess Myrcella as Queen of the Seven Kingdoms. Arianne feels treated poorly by her father and thinks Dorne will be ruled by Quentyn and Daenerys, ignoring the women's right to rule and inherit in Dorne being equal to the males. Actually Arianne had been secretely betrothed to Viserys Targaryen for years until her died at Vaes Dothrak at the hands of Khal Drogo.

During her secret plot to take Myrcella away from Sunspear and bring her to Hellholt, seat of Ellaria's father Lord Harmen Uller, to crown her, Arianne's party is intercepted and captured by Areo Hotah and Doran's guards at the river Greenblood. Arianne is betrayed for unknown reasons by one of her own supporter, Ser Gerold Dayne, who attempts to assassinate Myrcella. Gerold fails and flees from Hotah, and Myrcella loses an hear and is left disfigured. Kingsguard Ser Arys Oakheart is killed in the fight and Arianne Martell is imprisoned at Sunspear, while her dornish friends are divided by Doran in different places in Westeros: Sylva Santagar is married to Eldon Estermont in the stormlands, Andrey Dalt is sent to Ghaston Grey, and as punishment for committing treason, he is sent to the Free City of Norvos for three years, to join the service of Lady Mellario, Prince Doran Martell's estranged wife, and Garin is to spend his next two years in the Free City of Tyrosh. Later Doran tells Arianne his true masterplan and plot against the Iron Throne, revealing he's a good cautious strategist and was never cowering from the war and always wanted to avenge his sister Elia.

Doran orders a manhunt for Gerold Dayne, while Myrcella survives her injury. Ser Balon Swann of the Kingsguard arrives in Sunspear to deliver the skull of Ser Gregor Clegane. Ellaria is present at the feast and is later summoned to the private chambers of Prince Doran and is distraught when she hears Obara's statement on how the Mountain's death "...is a start". Ellaria wants it to be an end with Tywin Lannister, Robert Baratheon, Amory Lorch and now the Mountain dead, which is everyone who was part of the death of Elia and her children. Ellaria fears for her own daughters, who worship Obara, Nymeria and Tyene, and fears where the quest for revenge will lead them. Doran comforts her and tells her to go to her girls.

Areo Hotah thinks Ellaria is a strong and brave woman; even when she has tears in her eyes there is strength there. Doran thinks she has a gentle heart, which is worth more than anything.

Arianne has convinced Myrcella to lie to Ser Balon and claim that Ser Arys Oakheart was slain by Ser Gerold Dayne. Doran has planned for them all to travel to the Water Gardens, where Myrcella is staying, and where Balon can learn from Myrcella what Gerold Dayne has done. According to Doran's plan, Princess Myrcella is to plead with Balon to bring Ser Gerold to justice.

Doran thinks Daenerys is leaving Essos for Westeros and sends Myrcella back to King's Landing, but has his son Trystane remain in Sunspear, as he is informed about Cersei's plot to have him killed and blame Tyrion for his death. Tyene Sand is sent to King's Landing, disguised as a septa, to try to befriend the new High Septon of the Faith, while Nymeria Sand is to take the vacant Dornish seat in the small council. Meanwhile Obara Sand and Ser Balon Swann are searching for Gerold Dayne in Dorne.

At Meereen, after being refused by Daenerys for Hizdahr zo Loraq, Quentyn Martell tries to steal the dragons, Viserion and Rhaegal, for his father, but he's burned alive and dies a few days later. This might cause future enmity between Doran and Daenerys.

Ellaria is returning to her father's seat at Hellholt with her daughter Loreza.

Doran Martell receives a letter from Jon Connington, revealing the survival of Elia's son Aegon Targaryen, and informs Arianne of this news the same night the letter arrives. She eventually departs Sunspear, sent by her father to discover the truth about Aegon and Connington, and departs via ship to the stormlands with Elia Sand, Ser Daemon Sand, Joss Hood, Garibald Shells, Nate, Jayne Ladybright, and others.

Trivia

 * In the third book her character is still the same as she is in season 4. Oberyn and the Dornishmen arrive shortly before the Red Wedding occurs, and there are tensions between them and the Tyrells, Lady Olenna Redwyne calls Ellaria "the serpent's whore". She attends the royal wedding of Joffrey I Baratheon and Margaery Tyrell, and later witnesses Oberyn's brutal death at the hands of Ser Gregor Clegane.