From the Fire Emblem Wiki:

Roy is bookish young man that is eager learn and suddenly has to fill the role of a leader of the army. He is very collected and formal, as a result of being forced in the position of general . However, despite acting confident in front of his army, inwardly, he often doubts his competence as a leader and soldier. In private he is noted to be more relaxed and even somewhat clumsy, he is known to "dance with two left feet." A competent leader and warrior, Roy is an upstanding, thoughtful, and idealistic young man. While he would prefer to avoid bloodshed, he maintains a strong resolve to see peace return to Elibe.