Who is Cesar from Bel Canto: A Novel and what is their importance?

Cesar is a young boy from the jungle, as well as a member of the terrorists who invade the Vice-President's home. While there, Cesar doesn't draw any attention to himself until he sings...... and immediately captures Roxane's attention with his gift. Unfortunately, Roxane's plans to tutor him never come to fruition. Cesar is killed during the military attack.