Chapter One clearly indicates that the conflict Daniel has is with the Romans who have taken over his land and ensured that no Jew can be free and have possession of their own territory. Note how this is shown when Daniel looks down from the mountain where he and his fellow rebels are based and sees some Roman Legionaries:
Far down the mountain, on the narrow ribbon of road, he spotted a moving line that threw off reddish flashes of metal in the sunlight. Legionaries. At the sight, black hatred churned up in him. Out of habit he spat violently.
The way in which "Legionaries" is a one-word sentence emphasises the strong feelings that Daniel has when he sees these Roman soldiers. To reinforce that Daniel's central conflict is with the Romans who rule his people's land, the conversation he has with Joel indicates the level and depth of his hatred. Note he says "I curse the air they breathe," referring to the Romans. It is his hatred of Romans that led Daniel in part to run away and join the band of rebels that work to do what they can to impede the Romans, and it is this hatred too that Daniel needs to confront and deal with during the course of the novel.