Dawn of the Planet of the Apes
Foster was a survivor of the global Simian Flu Pandemic. He is first seen among Malcolm's Group and run over to Carver while pointing his gun at two apes before Caesar and the other apes arrive and shout (in English) for them to leave ape territory.
Foster returns to the forest with Ellie, Malcolm, Alexander, Carver and a few others to convince Caesar to allow them to generate electricity from the dam. Once, Caesar allows the humans to stay (after forcing them to give up their guns) he and the others discuss the apes. He then scolds and threatens Carver for coldly bringing up the deaths of Malcolm's first wife and Ellie's little daughter. Foster stays with the group, and is present where he is shown smiling as Caesar's infant son interacts with Ellie and Alexander.
When Carver threatens both of Caesar's sons, the apes demand that group leave Ape Territory but this decision is overturned by Malcolm and Ellie who help tend to the illness of Caesar's wife. The apes even promise to help the humans out but on the condition that Carver leaves, to which Foster happily decides to do himself. Forcibly sending Carver back to the car they arrived in while saying "See you tomorrow Asshole".
Foster and the others with the help of the apes then proceed to work on the dam. He pays witness to Caesar horribly beating up Koba for his insolence and watching the power in Human Colony being restored. When Koba shoots Caesar and frames Carver (thereby framing the humans), Foster flees with the others. His fate is unknown but he was presumably killed as he (and another member of Malcolm's group) fled in the direction the apes went in for the city. Also by morning; only Ellie, Malcolm, and Alexander hid and were they only ones who seemed to survive among the group.
His car was still in the woods leading to the possibility he was either killed or escaped into the deeper parts of the forest.