Seasmoke had been riderless ever since Laenor Velaryon faked his death and rowed away for a calmer life with his lover, Qarl Correy. Laenor abandoned Seasmoke and as the war of succession brewed between the two factions of House Targaryen, the Blacks hoped to reclaim him through one of their loyalists. Rhaenyra tried to put Ser Steffon Darklyn on Seasmoke as she'd found out that his great-great-grandmother Aeriana was a Targaryen Princess. As seen in House of the Dragon, this ill-thought-out attempt resulted in Ser Steffon and a Dragonrider's deaths.