Duke is an elite warrior and battlefield commander, who sits at the right hand of Cobra Commander. Until recently, Duke had no idea about his own past, and no understanding of the where he may have obtained his innate "above average" warfighting capabilities. This changed in 2003 when newly discovered documents linked Duke to "Project: NEO" a Eugenics and Genetic Engineering project started in 1958.

Further investigation revealed the existence of shadowy group of Nazi power brokers named "The Immortal". In a battle with a member of the group, Duke pulled the Immortal Guard's mask off and saw that the face of the enemy was identical to his own. The dying confession of the Immortal Guardsman suggested that Duke was the "final product" of Project: NEO.

Duke fights a battle on the ground against the Nazi troops, and in his heart against the mysteries surrounding his past.