Matrix is the leader of Liandri's team of cybernetics in Unreal Tournament 3. He is believed to be either a super-advanced machine or modified human being. He is fought by Reaper and his team, although little is revealed about his origins. Though the UT3 manual and website say that he might've been a "flesh and blood human" once but he "got the ultimate upgrade" courtesy of the Liandri Corperation.
There were 3 Matrix characters across the eras of UT. In the first one, Matrix was a corrupt male with his own head style. In UT2004, Matrix was a dark female Liandri robot, and shared the body with Enigma, another female Liandri robot. In UT3, Matrix received leadership of the Liandri team, and is of unknown gender. It has what appears to be 3 eyes and a smaller head than the other Liandri robots of the time.