Brandon Talbot is a prominent Callowan noble that serves as grandmaster of the chivalric Order of The Broken Bells.
Before the Conquest, the Talbot family was influential; it had ruled Marchford for five hundred years and Brandon's aunt Elizabeth, held to be the kingdom's greatest commander, was engaged to marry the Shining Prince, the son of Good King Robert. After the Conquest Brandon became a rebel, was caught but managed to escape; he then joined the many other young nobles who hid in the countryside training to be knights. After countess Elizabeth joined the Liesse Rebellion her estate was confiscated and eventually given to Catherine.
First introduced when Catherine returned from facing Winter in Arcadia, Brandon Talbot had spent a month as a prisoner in Marchford as he would only speak with Catherine. What the noble-born fugitive offered Cat was at least two thousand Callowan knights, although obtaining this would count as treason against Dread Empress Malicia.
Talbot is next seen after the Battle of Four Armies and One, where he led three thousand knights against the fae of the Summer Court. He is chosen to be grandmaster for the knights, by acclamation, and receives the formal title of commander in the Fifteenth Legion (the highest available without going through the War College).
Brandon Talbot ends up the spokesman for Callow's largest faction of nobles, the Regals, as he is moderate enough to know how much they can push Catherine, while still standing as a remain of Callow's once powerful nobles.
Brandon is a Callowan in his early thirties by Book 3, and is powerfully built with a thick beard and long hair with bangs held in a ponytail. He has dark hair and blue eyes. By the time of the Campaign against Keter, he has cut his hair short but kept the beard. 
Brandon puts impeccable effort into grooming his hair and beard. Even while on campaign Cat notices how neat he looks.
Brandon Talbot is the nephew of the Countess Elizabeth Talbot and was designated her heir, since she didn't have an children of her own.
Talbot is loyal to Catherine, and one of the few nobles she occasionally catches herself liking.
He has a strained but professional relationship with Juniper.