Warning: Spoilers ahead for episode five of the third season of “House of the Dragon” and the book “Fire & Blood.”

Alys Rivers may not be a dragon rider or a soldier, but the self-proclaimed “barn owl cursed to live in human form” is one of the most formidable figures in “The House of the Dragon.”

Played by Gayle Rankin, Alys is introduced in the second season of the HBO show as the unofficial maester of Harrenhal, an abandoned castle in the Riverlands held by House Strong. Alys’ job is to tend to the noble men within her walls (or what’s left of them).

However, despite her low status, Alys is quickly revealed to be more of a puppeteer than a simple servant.

Once Daemon Targaryen (Matt Smith) arrives with his dragon to claim Harrenhal, he finds an unlikely ally in Alys. While at the castle, Alys gives Daemon potions that appear to induce powerful visions. Using his mysterious influence, he guides the so-called “Rogue Prince” through his doubts, fears and regrets, culminating in the revelation that he is not meant to rule. At the end of the season, Daemon returned to his wife, Rhaenyra Targaryen (Emma D’Arcy), raised an army in her name, and promised to help her take the Iron Throne.

Although Daemon and Alys appear to form a bond, she keeps her true agenda hidden until the third season.

“I have done the queen a service. I put 40,000 rivermen at her disposal,” he tells Daemon in the second episode of the third season, titled “Queen’s Landing.”

“Tell him I want Harrenhal,” Alys continues. “I’ve lived there all my long life and seen it passed from hand to hand. And yet no one seems to appreciate it. Why shouldn’t it come to me?”

Daemon scoffs at his request. Alys is a bastard with no wealth, titles, or noble husband, which doesn’t put her anywhere close to competing for Harrenhal, even if the castle is said to be cursed. He dismisses Alys as just a midwife.

Daemon promises to talk to Rhaenyra about “some other reward,” but his dismissal of Alys may one day prove disastrous, especially if the series follows her story in George RR Martin’s original book, “Fire & Blood.”

Here’s why Alys is a character to watch in “House of the Dragon” as the Targaryen civil war continues to unfold.

Alys is said to be a witch and no one knows how old she is.

Daemon’s hallucinations at Harrenhal are due in part to the magic of the Old Gods, which is stronger in the presence of the Weirwood trees.

In the show, Alys appears to manipulate Daemon by channeling this magic. He also appears to have greensight, an ancient ability to see the future through symbolic dreams. (On “Game of Thrones,” Jojen Reed is a well-known ecological psychic, and some of the Stark children also have green dreams.) In the second season, he tells Daemon, “You will die in this place,” and later, “There are things older in this world than you or me, or living memory. You are not the player, but a piece on the board.” He even has intimate knowledge of Daemon’s family, including his brother, the late King Viserys.

In the book, Alys is not explicitly connected to the Old Gods, but is widely suspected of having some form of magic.

“Fire & Blood” is written like a history book, in which the characterizations and narratives often contradict each other. In the case of Alys: “A servant who dabbled in potions and spells, says Munkun. A forest witch, says Septon Eustace. An evil sorceress who bathed in the blood of virgins to preserve her youth, Mushroom would have us believe.”

Alys’ origin is also unclear. Some assume that Lord Lyonel Strong was her father, which would make her Larys and Harwin’s half-sister, but no one knows when she was born.

Alys apparently served as a wet nurse to “countless babies born to other women in Harrenhal”, including, possibly, Lyonel himself. All historians agree that he was at least 40 years old when the Dance of the Dragons began, although he looked much younger.

It’s possible that Alys uses dark magic to maintain a young body, just like Melisandre in “Game of Thrones.”

After Daemon leaves Harrenhal, Alys forms a bond with Aemond.

In the third season of “The House of the Dragon,” as in the book, Prince Aemond Targaryen (Ewan Mitchell) flies on his own dragon to destroy Daemon and retake Harrenhal, only to find the castle abandoned by his uncle.

Instead, Aemond finds the castellan of Harrenhal, Simon Strong, and his adult children. He kills them all.

“Thus the flower of House Strong, an ancient line of noble warriors who boasted descent from the First Men, came to an ignoble end in the neighborhood of Harrenhal,” the book reads. “No real Strong was spared, nor were any bastards except…oddly enough…Alys Rivers.”

“Fire and Blood” historians assume that Aemond views Alys as “a prize of war.” However, they also admit that Aemond seems to have an unusual fondness for Alys, especially given their age difference. (Aemond is around 19 or 20 years old at this point in the book). A source claims that Alys used love potions to seduce the prince.

Later, Alys becomes pregnant and says that she is pregnant with Aemond’s child, “the dragon’s bastard.” When Daemon finally flies away to confront his nephew, Aemond takes Alys to the duel on dragonback.

Aemond says that Alys told him where to find Daemon, which essentially led to both men’s deaths.

“He saw you in a storm cloud, in a mountain pond at dusk, in the fire we built to cook dinner,” Aemond tells Daemon. “She sees a lot and more, my Alys. You were a fool to come alone.”

Alys watches from the top of Kingspyre Tower in Harrenhal as Daemon and Aemond’s dragons attack each other and eventually as they all collapse into Gods Eye Lake and die.

He then disappears from the narrative until the Targaryen civil war ends.

After Rhaenyra’s fourth son, Aegon the Younger, is crowned king (and Aegon II’s daughter Jaehaera is crowned queen consort as her cousin’s bride), rumors begin to spread that Harrenhal is ruled by “a witch-queen of fearsome power.”

Flanked by hundreds of armed men and outlaws, Alys has taken over Harrenhal. He now claims that his son is the true heir of Aemond, “the rightful king of Westeros.” More rumors spread that he has a dragon inside the castle and that it can curse men to death.

However, before any of the king’s men can decide how to end his reign at Harrenhal, a plague ravages King’s Landing and drives Alys from their minds. Her story ends there and she is not mentioned again in “Fire & Blood.”

Ayomikun Adekaiyero contributed to an earlier version of this story.