|In or before 21 AC
Merrell Bullock was a knight in service to House Targaryen. He was the commander of the castle garrison at Dragonstone during the reign of King Jaehaerys I Targaryen. He had two sons, Ser Alyn and Ser Howard.
When King Jaehaerys was on Dragonstone during his regency, he spent every morning until midday in the castle yard training with sword, shield, and any other armament. Ser Merrell, along with his two sons, Ser Elyas Scales the master-at-arms, and knights of the Kingsguard sparred with the king.
When Rhaena Targaryen was given Dragonstone as her seat, Ser Merrell continued in his duties as the commander of the castle's garrison. In 54 AC, after the theft of three dragon eggs from Dreamfyre's clutch by Elissa Farman, Ser Merrell was suddenly relieved of his position, as Rhaena, furious by the betrayal by her former friend, became suspicious of everyone.