Lucerys Velaryon

Second son of Rhaenyra, made heir to Driftmark by his grandsire the Sea Snake over the trueborn cousins of his mother's line. Sent as envoy to Lord Borros Baratheon at Storm's End, he was pursued out of Shipbreaker Bay through a storm by his uncle Aemond on Vhagar, and on his own little Arrax he could not outrun her. Their bodies came ashore in pieces a fortnight later. His killing was the moment Westeros could no longer step back from the Dance.