Seasmoke

Seasmoke began the Dance as Laenor Velaryon's dragon and, in the strictest sense, ended it that way too — though the years between are stranger than most dragon histories bother to record. Laenor, heir to Driftmark and husband to Rhaenyra in a marriage the histories treat as a matter of politics rather than passion, is said by some accounts to have died at a rival's hand early in the succession crisis and by others to have simply vanished from the realm entirely, spirited away to begin a quieter life across the narrow sea. Whichever account the reader credits, Seasmoke went unridden and unclaimed for years afterward, kept at Dragonstone by a family unwilling, or unable, to let so fine a dragon go to waste.

The Sowing found him a second rider. Addam of Hull, a bastard of the Velaryon look raised among the shipwrights of Hull and long rumored — never confirmed — to carry Velaryon blood himself, walked up to Seasmoke at the height of the war's desperation and was accepted by a dragon that had refused every other claimant. It was, by the Citadel's reckoning, one of the rare unambiguously happy turns the Dance produced: a baseborn man and a masterless dragon finding each other exactly when both were needed. The happiness was brief. Addam flew Seasmoke into the three-dragon slaughter at Second Tumbleton alongside Tessarion and Vermithor, and none of the three beasts, nor their riders, came out of that melee alive.