Lou Marchbanks was a member of Fort Kohai, and husband of Ida Marchbanks. Lou disappeared from camp, as he was abducted by F.E.M.A. and experimented on; being turned into a Living Infected. After he was set loose, Lou was found by a Los Ceres patrol, and he viciously mauled and attacked them. They imprisoned him in a cell in Felipe's Compound, deeming him dangerous.
During Missing, the Survivalists are tasked by Ida to search for Lou and bring him back to the Fort. Regardless of the Survivalists' actions, a war between Los Ceres and Fort Kohai takes place, and eventually, the Survivalists make Felipe Espinosa surrender, and he is given to the Survivalists, but Felipe warns them of Lou's behaviour.
Outcome 1; Dead:
The Survivalists approach Lou in his cell, state that they believe he's infected, and they kill him.
Outcome 2; Dead:
The Survivalists bring him back to Fort Kohai, and Lou is met by Ida with open arms. However, Lou begins to act vicious and spiteful, and eventually he decides to "forget it," and attacks his wife. He is promptly put down by Fort Kohai and the Survivalists, making all of their efforts futile.