Gregor was aware of the witch's prophetic abilities.
His confidence in the witch's prophetic abilities stemmed from his familiarity with the world's trajectories.
In Aegon 276, Lord Tywin Lannister held a tournament at Lannisport to welcome King Aerys on his tour of the Westerlands.
At that time, Cersei Lannister, daughter of the Duke, Jeyne Farman of Fairy Isle, and Melaya Hesbane, daughter of Ser Tibert Hesbane, all came to Lannister Harbor. When the three children heard that the witch could foresee the future, their curiosity was piqued, and they secretly went to see the witch behind the adults' backs.
At that time, Melaya was the oldest, only eleven years old, Cersei was ten, and Jenny was the youngest, nine.
When the witch sat behind a long table piled with potion bottles, brushed aside her long hair, and opened her pale yellow eyes, Jenny Farman screamed and ran away immediately. Melaya and Cersei, however, stayed, insisting on hearing the prophecy about themselves, but the witch refused.
At this point, ten-year-old Cersei threatened the witch that if she refused to reveal the prophecy about her and Melaya's future, she would send her family's soldiers to burn down the witch's house and hang her from a tree outside the gate.
The witch was forced to reveal the prophecy about the future of the two girls.
The witch's first prophecy was that Cersei would marry the king and become queen at the age of seventeen.
This delighted Cersei, as her father would propose marriage to King Aerys at the banquet, hoping to marry her to Prince Rhaegar. Cersei had already met Rhaegar and was very fond of him. At that time, Cersei believed that the king she would marry seven years later would be Rhaegar Targaryen.
The witch's second prophecy was that Cersei would have nineteen children, sixteen of whom would belong to the king, and the remaining three to Cersei. At the time, Cersei didn't understand, but now she does.
The third prophecy states that Cersei's children will be shrouded in gold, and that she will be strangled by her brothers while she weeps for the loss of her children.
The first two prophecies have now come true, while the third prophecy is accompanying Cersei, casting a shadow over her entire life.
The witch also foretold the future of the eleven-year-old girl Melaya, telling her that her desire to marry Jaime would not be fulfilled, and that that very night would be her death day.
"Little sister, your death will come tonight. Haven't you smelled her scent yet? She's right beside you." The witch hinted to Melaya that the murderer of Melaya was her playmate Cersei.
Cersei grabbed a medicine bottle from the table and smashed it into the witch's eyes.
Melaya did not believe the witch's prophecy.
However, the prophecy came true; Melaya fell into the well and drowned that very night. Because of her closeness with Jaime, Cersei saw her and lured Melaya to the well, then pushed her in.
Melia's body was retrieved from the well the following afternoon.
Gregor now knows that this was not the first time Cersei had killed someone.
Cersei, Jeyne Westerling's sister, is a beautiful but ruthless monster who is not easy to deal with.
Also in that year, not long after the incident, it happened at the pool in Cersei's house. Cersei tricked her three-year-old brother, Tyrion Lannister, into going to the pool to look at the fish, and then pushed Tyrion into the pool.
Tyrion Lannister struggled in the water, the noise alerting the servants, and he was rescued. When his father asked Cersei, she said that Tyrion had accidentally fallen into the pool.
Tyrion Lannister was hated by his father Tywin Lannister and disliked by his sister Cersei because he was born with a deformity and his mother died in childbirth.
Gregor also knew that Cersei had secretly taken scissors to kill Tyrion shortly after his birth, but her twin brother Jaime Lannister stopped her.
Cersei attempted to murder Tyrion several times but failed, though eventually Tywin Lannister learned of it. Unable to deny Tyrion's Lannister lineage before the Seven, and feeling a responsibility to protect him despite his reluctance, Tywin, out of family honor and faith in the Seven, assigned servants to care for Tyrion, forbidding Cersei from approaching his deformed brother. Thus, the impish Tyrion Lannister finally grew up safely.
Because Gregor knew these secrets unknown to outsiders, he had no doubt about the witch's prophetic abilities.
With such a powerful prophetic wizard among his relatives, Gregor decided to make use of him.
In this fantasy world where mysticism will flourish with the appearance of dragons, Gregor needs not only fierce generals and skilled soldiers, but also the help of wizards with magical abilities.
The witch was the best candidate in his opinion.
Because the witch was a sorceress, she spent her days and nights tinkering with all sorts of strange and wonderful potions, and both of her sons left her. Neither of them wanted to become a lowly merchant like their father, nor a mystical sorceress like their mother. The two brothers set out on their own, working hard to earn a noble title from Lord Tywin Lannister – that was their ultimate goal.
Therefore, after her husband's death, the witch lived alone like an old woman, even though she had a son in Lannesport.
Although the two sons founded House Spicer, they did not outlive the witch and died. One son left behind Rover Spicer and Sybil Spicer, while the other son left behind Samwell Spicer.
Although she had descendants, the priestess had grown accustomed to living alone. After her son's death, her grandchildren had no contact with her whatsoever.
Gregor was the first person to come to the witch, representing the descendants of the Spicer bloodline.
Regardless of what Jenny and Earl Gavin thought, Gregor was determined to bring the Sorceress to Clegane Keep. He had already planned this when he was building the Seven Temples; the Seven Temples in Clegane needed a priest, his future legions needed a maester, and a military priest. By all accounts, the Sorceress was the best choice.
Guided by Gregor's enthusiasm, Jenny and Earl Gavin approached the witch and met her as a relative.
The witch asked, "Gavin, how is Sibel?"
"She's fine, Grandma."
"Where's that kid, Rofort?"
"He's doing well too."
Lov Spicer was Jenny's uncle. After Hebeil married Earl Gavin, Lov followed his sister to Cliffrock. Lov was a fierce warrior with a broken nose, a scarred face, and a menacing appearance.
Rover did not accompany Earl Gavin to Casterly Rock this time. Whenever Earl Gavin had to leave Casterly Rock, Rover would act as the acting lord of the city. One of them would always remain in Casterly Rock.
"Grandmother, I have built a shrine to the Seven Saints for you, constructed a pharmacy just for you, and hired servants specifically for you. Please come with us to Clegane Castle, and from now on, we will take good care of you." Gregor spoke respectfully and earnestly.