The latest episode of 'House of the Dragon' dropped a major clue about why Addam and Alyn of Hull are going to be important characters

• "House of the Dragon" has introduced Addam and Alyn of Hull, brothers affiliated with the Velaryon fleet. 
• In "Fire and Blood," the brothers are pivotal characters.
• 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 two, and for the book "Fire and Blood."

Another week, another new character introduction that you'd best not forget on "House of the Dragon."

Viewers met Alyn of Hull in episode one. Corlys Velaryon approaches Alyn, who gives him a report on the status of his ship. Alyn also presents Corlys with a dagger — one that Corlys commissioned as a gift for Lucerys, his now-deceased heir. But there's one more crucial piece of information Corlys gives us: Alyn was the one who saved his life, and Corlys feels that he owes him a debt.

In episode two, we meet Alyn's brother Addam, a shipwright from Hull working on the Velaryon fleet. Addam urges his brother to cash in on his favor from Corlys, and sail with him. Alyn reminds him that Corlys never offered.

"Do not be foolish, Alyn. To serve with the Sea Snake is to make your fortune. Had I such a chance, I would leap at it," Addam tells Alyn.

Alyn reminds his brother that there's a real, impending war. Addam thinks that Corlys owes Alyn (presumably for saving his life), but then cryptically adds that Corlys owes both of them.

The writers are telegraphing pretty hard that these are characters we'll see again — here's what happens to them in "Fire and Blood."

Major potential show spoilers ahead.

Addam of Hull becomes a dragon rider

In the events of "Fire and Blood," Jaecaerys Velaryon promises wealth to any man able to claim a dragon. Addam successfully claims Seasmoke, the former dragon of Laenor Velaryon, Rhaenyra's husband.

It's likely the show will go this route too; 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!

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 dragon riders, some of whom betray Rhaenyra. Eventually, he and Seasmoke die in a dragon fight.

Alyn of Hull becomes Corlys Velaryon's heir

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 his throne. After Rhaenyra's death, and with Corlys sequestered in King's Landing, Alyn assumed control of the Velaryon fleet.

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