Who is Brigadier-General Sean Courtney from A Sparrow Falls and what is their importance?

After four winters in France, B.G. Sean Courtney is a tough and often unpredictable leader. He enjoys an informal style, where he is likely to show up unannounced even on the front lines unattended by even his own staff. His impromptu visits cause his subordinates much dismay, but Sean enjoys the panic his sudden arrivals have been known to cause. He is a tough and unorthodox leader, who has been compared to a bull elephant, but having survived the Boer War, he is more comfortable with his men than with the leaders of equivalent rank and status.