"The Destructors," by Graham Greene, could have three antagonists, depending how you look at the story. At first, it seems that T is the antagonist. Blackie is presented as the true leader of the group, concerned about keeping the gang together. But T usurps Blackie's power with his plot to destroy the Thomas house. The struggle for leadership between T and Blackie serves as one of the major conflicts in the short story. Here we see the conflict between a more benevolent and somewhat harmless leader and a ruthless, more dangerous one.
Mr. Thomas could be considered to be the antagonist to the gang of boys. They must complete their mission to destroy his house before he comes back to stop them. When he arrives early, the boys must use their wits to detain him in the loo. T is a master of manipulation here.
But most likely the true antagonist is the setting itself. It is post-war England. The children have been stripped of their innocence, their childhood. They live in bleak, war-torn surroundings, where beautiful objects of the past have been destroyed. Their parents are non-entities in the story, and the children are left to their own devices. They mimic the actions of their predecessors, choosing to destroy rather than create. Greene shows us how closely related the two processes are. It takes just as much discipline, teamwork, creativity, intelligence, and energy to destroy as it does to create. Mankind is often faced with this choice and often chooses as the gang the does.
Even the lorry driver at the end of the story is not horrified by the destroyed house. He only laughs. He too is numb to and accepting of destruction.