Chiara, Duke Leto, and Kailea from the Japanese cover of Dune: House Harkonnen
Kailea Vernius (? - 10174 AG), born in planet Ix, member of the House Vernius. Daughter of Earl Dominic Vernius, and Lady Shando Balut. Sister of Rhombur Vernius.
First concubine of Leto Atreides. Mother of Leto's first child, Victor Atreides.
She had copper-dark hair, thin arched eyebrows, striking emerald eyes, and a generous, catlike mouth above a narrow chin.
History
As member of the Great House Vernius, Kailea lived with her family in the underground of the planet Ix. One day she met the young Leto Atreides (who has 14 years old, nearly the same age that Rhombur), who traveled to the planet to visit her family and take studies with her brother.
Shortly after, the planet was overthrown by the Imperial Sardaukar and Bene Tleilax. Kailea, along with his brother Rhombur and Leto, narrowly escaped to the planet Caladan, living as refugees.
Over time, she and Leto eventually fell in love and bore their son, Victor Atreides. It was a time in which both were very happy. Some time after, an old woman named Chiara joined to the House Atreides, in order to serve to the Ducal concubine as Lady-in waiting.
After several years, Kailea became less pleased with her marriage. As House Vernius became a renegade House of the Landsraad, she wanted that their son Victor be appointed heir of the House Atreides, but Leto refused continuosly to do that.
When the Bene Gesserit Jessica joined House Atreides in Caladan as second concubine of Leto, Chiara quickly pointed out to Kailea that she and her son may be displaced. Kailea was also aware of an offer of marriage to Leto, extended by Archduke Armand Ecaz for his surviving daughter, Ilesa Ecaz.
This facts weight heavily on Kailea's mind. Chiara guided Kailea into beliving that the only way to future happiness was to kill Duke Leto. Both orchestrated a plot to assassinate Leto in a staged ship crash, by having Chiara placed a large bomb aboard Leto's skyclipper planetary cruising ship.
Plot to Kill Leto
Kailea began an affair with House Atreides ammunition keeper, Swain Goire, and unbeknownst to him, took his key of the Atreides' armnaments depot from his belt clasp. Kailea gave it to Chiara, who takes from the Armory rigged a time bomb, and placed it into Leto's skyclipper. All of Cala City had been abuzz, as Leto had planned for weeks to visit Caladan's Western Continent in the engine-powered dirgible. Chiara notified Kailea that the bomb had been placed on the blimp-like craft before it had departed skyward.
However, Kailea was latter notified by Goire that her brother Rhombur Vernius and her beloved son Victor had accompanied Leto. The explosion and subsequent crash, resulted in the maiming of her brother and the death of her 6-year old son, Victor. Leto had survived.
Deeply depressed, and knowing the her judgment soon awaited her, Kailea summoned Chiara to her bedroom. Confronting Rash-Olin, she quickly realized that she was manipulated by her assistant Chiara, who was actually a spy for House Harkonnen. Before Chiara could defend herself, Kailea plunged a blade she had snatched from Goire minutes earlier, and stabbed her deeply in the heart. Then she stabbed her again and pierced Rash-Olin's heart.
When Thufir Hawat and other Atredies' officials came to arrest her, she committed suicide by jumping from a balcony in Castle Caladan.
Behind the Scenes
One of the continuity issues regarding House Vernius (q.v.), is that there is no mention of Kailea or of Victor Atreides in any of Frank Herbert's Dune novels. His works indicate that Paul was Leto's first and only child, and that Jessica was Leto's first and only concubine. This is further supported by the fact that there is no mention of Victor, when Atreides family members are revered by others, in the original novels.
This plot point of the Prelude to Dune series, that Leto had concubines while being married, is inconsistent with the honorable characteristics bestowed upon him by Frank Herbert.