her retinue sat their mounts behind her : ser boros blount of the kingsguard , wearing white scale and his favorite scowl ; ser balon swann , bow slung from his silver-inlay saddle ; lord gyles rosby , his wheezing cough worse than ever ; hallyne the pyromancer of the alchemists ' guild ; and the queen 's newest favorite , their cousin ser lancel lannister , her late husband 's squire upjumped to knight at his widow 's insistence .