He is from the CIA and has the rank of a colonel. He is covertly combating a rebel movement supported by the Russians in ValVerde. He was also a comrade of Dutch. He also fought with him, but his activities inside the CIA have made him rusty regarding his former activity.
He enlists Dutch and his team with the purpose of finding a team of his that was captured by them, find a team of his lead by Hopper to rescue them, a team that disappeared, and kill Russian advisors there too, who are planning an invasion with the guerillas. He tricks Dutch for this mission knowing he wouldn´t accept it by making him believe he is there to save people, among them a minister.
They find Hopper and his team skinned alive and kill the Russian advisors later, while watching Dillon´s men die. Dutch realises he was tricked and is angry with him because of it.
This trick causes problems between him and the others, but they are forgotten, when they realise they are being hunted down by someone, who butchering them like Hoppa´s team.
He is the last to believe that the creature hunting them is an alien, when it begins to kill Dutch´s team despite of evidence that supports is. Still, he grudgingly helps Dutch´s attempts to stop it. He believes differently when he sees it decloaking and cloaking with his own eyes.
He tries to kill it and save what is left of Dutch and his team as penance for what he did and to avenge Hopper´s death. He goes after it with Mac, who wants to avenge Cooper´s death.
He is killed by the creature in the attempt together with Mac.
- Carl Weathers was always the first choice to play Dillon.