The latest episode of 'House of the Dragon' finally confirms Addam and Alyn of Hull's importance

• "House of the Dragon" season two introduced Addam and Alyn of Hull.
• In "Fire and Blood," the brothers are pivotal characters, and Addam has a big moment in episode six.
• Here's what happens to them in the books — and what may happen on the show.

Warning: Spoilers ahead for "House of the Dragon" season two, episode six, and for the book "Fire and Blood."

Addam and Alyn of Hull are finally becoming major players in this week's "House of the Dragon," as one of the brothers becomes a dragonrider.

When the Hull brothers were first introduced in the early episodes of "House of the Dragon" season two, they initially seemed like random minor characters amid the show's big cast.

But in recent episodes, the show has given more hints that this pair will be really important in the impending civil war.

In the latest episode, Corlys Velaryon asks Alyn to serve as his first mate on his ship when they next ride out to sea. Alyn reluctantly accepts despite previously expressing that he didn't want any reward from Corlys for having pulled the older man from the sea, saving his life.

The reason for Alyn's rejection is finally addressed in the same episode. While Alyn is arguing about the situation with his brother Addam, Alyn says that Corlys will never accept them as his sons. It is the first time the series has openly discussed that both men were fathered by Corlys, though earlier episodes established that they (and Corlys' late wife, Rhaenys) knew the truth about their parentage.

But it's Addam who has the most monumental moment in Sunday's episode. The riderless dragon Seasmoke chases and eventually corners him. But instead of killing Addam, the dragon chooses the young man as his new rider.

Addam is the first person not of noble birth to ride a dragon on the show, making a big development for the series. But fans of "Fire and Blood," the series' source material, are likely not surprised by this turn of events.

Here's what happens to Addam and Alyn in "Fire and Blood."

Addam of Hull becomes a dragonrider

"Fire and Blood" recounts how Rhaenyra's son, Jacaerys Velaryon, promises wealth to any man able to claim a dragon. Addam successfully claims Seasmoke, the former dragon of Laenor Velaryon, Rhaenyra's late husband.

The series seems to be adapting this storyline in a different way. Firstly, in episode two, Addam observes a pale dragon resembling Seasmoke flying above him as he picks up a crab on the beach. Pretty strong foreshadowing!

Then in episode six, Rhaenyra tries to recruit a new dragonrider after Jacaerys makes the suggestion. Her chosen rider, Ser Steffon Darklyn, the Lord Commander of her Queensguard, is killed by Seasmoke, and the dragon flies off to find Addam instead.

In the book, both Alyn and Addam are described as having silver hair and purple eyes, hallmarks of Valyrian descent. Their mother was a woman named Marilda, who gave birth to Addam when she was 16, and Alyn when she was 18. Both of her sons served on her fleet of ships.

Marilda claimed that her sons were Laenor Velaryon's bastards. But Mushroom, who provides one of the historical accounts referenced in "Fire and Blood," posits that Corlys was their father instead. After Addam successfully bonded with Seasmoke, Corlys asked Rhaenyra to legitimize him as a Velaryon. She did so, making Addam Velaryon the heir to Driftmark.

As a dragonrider, Addam played a crucial part in the war. He eventually helped to claim King's Landing for Rhaenyra, and defended it while Daemon sought out Aemond and Vhagar.

Later in the war, Addam's fate is loosely tied to that of the other dragonriders, some of whom betray Rhaenyra. Eventually, he and Seasmoke die in a dragon fight.

Alyn of Hull becomes Corlys Velaryon's heir

According to the book, after failing to locate the wild dragon Grey Ghost, Alyn unsuccessfully tried to claim another dragon called Sheepstealer. He was wounded in the process when Sheepstealer set his cloak aflame, but Addam and Seasmoke saved him.

Later, Corlys asserted that both Alyn and Adam were Velaryons, and suitable heirs to the Driftwood Throne. After Rhaenyra's death, and with Corlys sequestered in King's Landing, Alyn assumed control of the Velaryon fleet.

The TV series seems to be foreshadowing this eventual storyline with Alyn becoming Corlys' first mate in episode six.

Eventually, Alyn became Corlys' chosen heir. After Corlys' death, he became the new Lord of the Tides, and eventually wed Baela Targaryen.

"House of the Dragon" season two airs Sundays at 9 p.m. ET on HBO and is streaming on Max.