Addam of Hull
Alyn's elder brother, another of Hull's conspicuously silver-haired sons — until Seasmoke, riderless since Laenor, chose him out of the sky and made the whispers unnecessary.
A soul of House Velaryon, born at Driftmark, sworn to The Dragonseeds.
The fuller tale
Season Two
In Smallfolk — Ran from a dragon and got chosen anyway — the first of the seeds. Seasmoke does his own choosing: he hunts down Addam of Hull on Driftmark and takes him into the sky alive. Addam's claiming shows the way: Rhaenyra summons Targaryen bastards and dragon-blooded smallfolk from every brothel and shipyard — the Red Sowing.
Where they stand. Driftmark.
Their story
Alyn's elder brother shares the same conspicuously silver Velaryon hair and the same unacknowledged parentage, another of Hull's shipwright sons whom the court's whispers link, never quite openly, to the Sea Snake's own bloodline.
His moment arrives when Seasmoke — riderless since Laenor's departure from the story, and unclaimed by anyone in the years since — chooses Addam out of the sky during the Sowing, the desperate period when the black cause opens dragon-claiming to anyone with the blood and the nerve to attempt it. The dragon's choice makes the whispers about his birth essentially irrelevant; a dragon does not lie about lineage.
Legitimized in recognition of both his birth and his new bond, Addam fights the war's final campaigns as a fully acknowledged Velaryon, flying Seasmoke in battles that ask considerably more of him than his shipyard origins ever prepared him for.
How it ends for them
On the page. Fell at Second Tumbleton, proving a bastard's honor (F&B, ch. 7)
Named a traitor for his blood when the Betrayers turned, Addam Velaryon — legitimized by the queen — spent his death proving them wrong: he fell at Second Tumbleton riding Seasmoke against the greens' whole host. 'Loyal,' reads the stone the Sea Snake raised him.
The series has not yet reached the battle in which Addam dies; his fate remains ahead of the current seasons.
Fire & Blood has him fall at Second Tumbleton, in the same chaotic engagement that claims Hugh Hammer and very nearly costs the greens the war entirely — flying Seasmoke against the greens' whole assembled host even after his fellow dragonseed Ulf the White turns traitor, proving with his death exactly the loyalty the whispers about his birth once made people doubt. The Sea Snake, the book notes, has a headstone raised for him reading simply 'Loyal' — the shortest epitaph in the entire history, and among its most sincere.
Their chapters, book by book
Fire & Blood — The Dance of the Dragons 2 chapters that name them
Where the page and the screen part
The show and the book agree closely on Addam's arc — the Sowing, Seasmoke's choice, and his legitimization are treated with similar weight in both tellings, one of the clearer points of continuity between the current aired seasons and the book's fuller account of the dragonseed campaigns.
Their journey
Where the two tellings send them to the same place the road runs whole; where they part, the screen keeps the left and the books the right.