The 'House of the Dragon' season 2 finale introduces a mysterious new character. Here's who Brynden Rivers AKA Lord Bloodraven is and what happens to him in the books.

Brynden Rivers, or Lord Bloodraven, appears to Daemon Targaryen in the "House of the Dragon" season two finale. Here's why he's important in the "Game of Thrones" franchise.

• The "House of the Dragon" season two finale briefly introduces a mysterious new character.
• Brynden Rivers, also known as Lord Bloodraven, appears to Daemon Targaryen (Matt Smith).
• Here's why he's important to the "Game of Thrones" franchise.

Warning: Major spoilers ahead for "House of the Dragon" season two, episode eight.

After spending most of "House of the Dragon" season two dealing with incestual hallucinations and prophetic visions, Daemon Targaryen (Matt Smith) has one last dream in the final episode. It introduces Brynden Rivers, also known as Lord Bloodraven.

Alys Rivers (Gayle Rankin) — who is seemingly unrelated to Brynden — takes Daemon to the weirwood tree in Harrenhal, and he puts his hand in the blood pouring from the bark, which starts his dream.

During it, Daemon then sees glimpses of the undead White Walkers and Daenerys Targaryen (Emilia Clarke). This suggests he knows Westeros will have to battle the icy zombies in the future.

This alludes to "Game of Thrones," which became a pop culture juggernaut shortly after it started on HBO in 2011. The supernatural threat of the White Walkers was teased in the first season, but the overarching storyline didn't really come to fruition until seasons six, seven, and eight.

The dream forces Daemon to realize that he has to put aside his bitterness over the fact that Rhaenyra Targaryen (Emma D'arcy) is the heir to the throne, not him.

At one point, he also sees a man with long white hair and a red birthmark on his face. Readers of the books will know that this is Brynden Rivers.

Brynden was a Targaryen loyalist during the Blackfyre rebellion, which takes place around 60 years after the events in "House of the Dragon." He's nicknamed Lord Bloodraven because his red birthmark resembled a raven.

He is the bastard son of King Aegon IV Targaryen, and eventually becomes the Lord Commander of the Night Watch at the Wall — but disappears into the north after a decade of protecting it.

Rivers becomes the three-eyed crow, a magical greenseer so finely in tune with the mystical nature of the world that he can see into the future. He can also skinchange, and take control of animals' minds.

In George R. R. Martin's book, "A Dance of Dragons," Bran Stark finds the ancient Three-Eyed Crow still living in a cave after more than 50 years, entwined in a wooden throne made of twisted weirwood roots.

If that sounds familiar, it's because "Game of Thrones" adapted Rivers into the Three-Eyed Raven — not a crow — played by Max von Sydow in the later seasons.Brynden Rivers is the three-eyed raven who teaches Bran Stark

While Martin's books explicitly state that the Three-Eyed Crow's real name is Brynden, "Game of Thrones" doesn't reveal the Three-Eyed Raven's name while he trains Stark (Isaac Hempstead Wright) to become his successor. Sydow's character also doesn't have the same red birthmark on his face as Brynden does in "House of the Dragon."

It's possible this could be explained in "House of the Dragon" with the idea that the Three-Eyed Raven simply managed to change his appearance over time.

The other possibility is that he isn't the same character at all. "Game of Thrones" notes that the Three-Eyed Raven was over 1,000 years, old but Brynden is only meant to be a few hundred years old by the time he meets Bran.

It's unclear what happens to Brynden after 2011's "A Dance of Dragons," because Martin hasn't finished the final two books, "The Winds of Winter" and "A Dream of Spring."

But in "Game of Thrones," the Three-Eyed Raven shows Bran the truth that Jon Snow (Kit Harington) is the son of Lyanna Stark (Aisling Franciosi) and Prince Rhaegar Targaryen.

Shortly after, the Night King and the White Walkers assault the cave where the Three-Eyed Raven lives. While Bran manages to escape with his companion Meera (Ellie Kendrick), the Night King kills the raven by cutting him in half.

It's not clear whether Brynden/the Three-Eyed Raven will suffer the same fate in Martin's future books.