In Half Of a Yellow Sun who is Madu and what does he contribute to society?

Nigerian author Chimamanda Ngozi Adichie tells the story of the Nigerian Civil War around the late 1960s aka "The Biafran War", a conflict caused by cultural, ethnic and economic tensions between several groups of people in the country, "Half Of a Yellow Sun" is the novel telling that story from the perspective of it's characters; Madu is one of those characters, a military official, who served first in the Nigerian army and later on in the Biafran army, he acts as a catalyst throughout the development, putting pressure on other characters, he contributes to society through his iniciative of letting the world know the truth about the conflict by pushing Richard (representating Britain and the western world) to tell the story.