Ooh, a bevy of choices. Let’s pick the violent men. First, there is the man in the red sweater that teaches Buck what it means to fear a club. Later it is Hal, before the team falls through the ice. The conflict with these men as he learns to withstand hardship and forced submission is what drives Buck towards a harder and wilder version of himself,
It is the wild that makes things difficult for Buck, what with the freezing temperatures and the ice breaking and everything. We’re not sure if we would necessarily call it an antagonist, but it’s an interesting point to ponder.
There’s also Spitz, who is not a great guy. This is most likely the natural choice for antagonist (which is why we put it at the end, so you could consider the other possibilities.). Spitz is cruel, violent, and, of course, antagonistic to all the other dogs. But he also has some strange similarities to Buck. Keep reading. More in a moment.