Backstory
Rosier was a seasoned and experienced veteran who served in the 31st Company. Rosier was best friends with Cosal and both served in the 31st for several years before they met Macai. Rosier himself had been in the 31st for 11 years when book 2 of Avatar: Macai's Journey took place. Rosier offered important insights to soldiers in battle and often fought as a field officer. initially signed up when he was 16 years old and had a length career in the Hundred Years War.
Abilities
Rosier was experienced and knew how to perform different tricks while fighting. He was one of the better firebenders in the 31st but due to his old age he would eventually begin to tire if he fought for over 30 minutes without a breath or if he fought at high intensity for more than 15 minutes. Rosier's timing was excellent, his attacks were accurate, and he was agile for someone his age.