At first glance, Samir Duran is a defected Terran Confederate Lieutenant who enters service under the United Earth Directorate. However, he would soon betray them and become infested, serving under the queen of Blades instead. Yet, this turns out to be another ruse - Duran seems to be serving someone even greater.
In reality, the unnamed entity known by the alias of Samir Duran, and later known under the name Emil Narud, is an ancient Xel'Naga serving Amon and the secondary antagonist of SC II.