Background

Soldier of Fortune was developed to be based on the Soldier of Fortune magazine. 
About midway through the game's development, Raven Software hired a professional 
mercenary, John Mullins, to act as a consultant on the game for purposes of 
realism and accuracy. A fictional version of Mullins was eventually made 
into the game's main character.
Soldier of Fortune was one of the first "real-world" first-person shooters, 
with modern weapons and human opponents, as opposed to more fantasy/sci-fi 
oriented games like Doom or Duke Nukem 3D.