We've been through hell together! We spent four years, FOUR YEARS fighting that virus, and another four fighting each other! It was chaos! But do you all know what we're up against?! And I want you to know, it's not just about power! It's about giving us the hope to rebuild, to reclaim the world we lost!
I'm saving the human race!
~ Dreyfus's final words.
Dreyfus is the secondary antagonist of Dawn of the Planet of the Apes. He is the leader of the Human Resistance, and although not necessarily evil by any means, Dreyfus is willing to take extremist means to save and protect humanity.
Dreyfus is a former police chief who is appointed as the leader of the human resistance. Having experienced personal loss (his wife and two sons having succumbed to the Simian Flu), Dreyfus sees Caesar and his colony as a threat after discovering an ape encampment at a local power station. Seeing no other solution, Dreyfus has one goal: wipe them out. He is Malcolm's boss, who he works closely with, they have very different views on how the apes should be handled. During the middle of the movie, Dreyfus and his surviving crew prep for battle as the apes attack. The apes ultimately break through the human's defense and Dreyfus escapes, leaving the humans to suffer.
They're animals! They attacked us!
~ Dreyfus argues with Malcolm, doubting the apes want peace.
Near the climax of the film, Dreyfus, encountering Malcolm in an abandoned underground bunker reveals to him that he and his men have made contact with a military base up north and they are already on their way to help them fight the apes. When Malcolm discovers that Dreyfus has set up a bomb ready to be detonated, he then threatens Dreyfus and his two men with a rifle and orders him to deactivate the bomb. Dreyfus refuses and has no choice but to willfully sacrifice himself and his two men with the bomb detonator for the survival of the human existence and for the extinction of the ape colony. Despite Dreyfus's efforts, Malcolm manages to escape and survive the explosion and the apes survive the bomb and the fall of the tower, with the exception of Koba (who falls to his death shortly after).
Gary Oldman mentioned in an interview that Dreyfus was the designated leader of a community of humans who were lucky enough to survive the flu, the disease and ensuing social uprising following the global pandemic at the end of Rise of the Planet of the Apes. Oldman's character was a police officer before the fall of civilization, and has subsequently been elected to lead over his group of survivors. The human community, desperate to find power, ventures off to a nearby power station, to see if it's still operational. There, the humans "discover that there's a whole community of apes living there. We believed that they were all completely fire-bottomed and wiped out". They're not wiped out yet, but that might change when Oldman finds out about the apes. "There's only one answer for him; Wipe them out", he teased.
Dreyfus lost both his wife and two sons to the Simian Flu which further fueled his belief that Caesar and his colony need to be wiped out in order to ensure humanity's survival.
It is speculated that he may be a counterpart to Governor Kolp, an antagonist in Battle for the Planet of the Apes since both are leaders of the survivors and bent on the destruction of the apes.
Ironically, though being advertised as the main villain in order to hide Koba's true role as main antagonist, Dreyfus himself is the perfect human counterpart of the said true main antagonist for the following reasons;
Dreyfus and Koba are hellbent in the destruction of each other's race (Dreyfus want to exterminate all apes while Koba wants to eradicate all humans until none of them are left).
Both are indifferent with their ally's intention to create the peace between their race, whom coincidentally, happened to being counterparts on each other (Dreyfus ignores Malcolm's intention to give the ape's a chance to co-exist peacefully with mankind while Koba was furious when he found out that Caesar intended to ensure that apes and mankind are able to live peacefully through his actions).