Describe the character Captain Nathan (Tom Cruise) at the beginning of the story?

When Algren first arrives in Japan, he is cold and detached, an alcoholic, whose only purpose is to train the Imperial Japanese Army. He has little interest in who or what they will be fighting. Over time, however, Algren becomes attached to his new home and wishes to be a part of its culture. In response, he is overcome by his past and decides that rather than participating in a massacre, he can help to prevent a repeat of the Native American massacres in the United States... he might even gain redemption.