Gwayne Hightower

In 111 AC, at a tournament held in King's Landing, Ser Criston Cole knocked him from his horse.

After King Viserys I died in 129 AC, with war looming, his father Ser Otto Hightower, then Hand of the King, gathered at the Red Keep the head of the City Watch along with its seven captains, to sound out where their loyalties lay.

The commander and two of his captains turned out to be close to Princess Rhaenyra Targaryen and were thrown in a cell for it. Luthor Largent, one of the trusted captains, took command of the Watch, and Ser Otto set his own son as Largent's lieutenant, with orders to keep an eye on him in case he switched sides.

Not long after, King Aegon II sent an envoy to Dragonstone to sound out peace with his half-sister Rhaenyra. Grand Maester Orwyle led the party, and among those sent were Ser Gwayne and Ser Arryk Cargyll.

The envoys laid out their terms, and the island turned them down flat: they were sent away without an agreement.

When King's Landing fell to the Blacks, the men in charge of the City Watch — its seven captains — ended up prisoners of their own troops, most of whom had turned to Prince Daemon Targaryen, the Watch's former commander and the one who had built it into the formal body it now was.

Ser Gwayne was seized while running for the stables to raise the alarm. He was brought before Luthor Largent and accused him of turning his cloak; Largent answered by showing which side he was truly on, killing him with a sword thrust to the belly.