Nathaniel Brown is the main character of City 17.
Nathaniel Brown, also known as Citizen 01907, appeared as one of the many citizens in City 17 who were enslaved by the alien empire known as the Combine. After being relocated to City 14, he grouped up with his brother Montgomery Brown and their childhood friend Sarah Dark and joined the resistance in order to help out with their plans to save the human race. Around the time of Gordon Freeman's fight against the Combine, Nathaniel was employed by the mysterious G-Man to help in the assassination of administrator Wallace Breen. Once Nathaniel carried this out, he was betrayed by G-Man, and they became sworn enemies.
In the years of the new era of humanity following the Combine's defeat, Nathaniel became a career criminal in the New City 17 and tried to make a name for himself. During his many conflicts, he began uncovering a conspiracy by a group known as the Clandestine Corporation, who planned to enslave the human race. This battle came to its climax when Nathan destroyed their leader the Dark One, and was presumed dead when their base was destroyed.
Nathan resurfaced a year later and began working as a private investigator and bounty hunter, but began to succumb to mental illness.