Last Man Standing
From Halopedia, the Halo Wiki
The Last Man Standing is the name given to the last member of the Human team during any Infection match. When a Human team member becomes this, the Game Announcer will say "Last Man standing." Anyone who becomes the Last Man standing will also have a Waypoint above their heads, making it easier for Zombie team members to find them.
There can only be one last man standing, and their various settings can be changed from that of the normal humans in the settings. The player also receives a game medal, for being the last man standing, and an icon on the bottom of the screen, reminding the player of their perilous and likely short lived position as the last human alive.
