Adam is a very minor character in this story who is first introduced in Chapter Four, which is when Falconer and Widge arrive at Leicester. As they arrive at the house where they are going to stay, Widge and Falcon nearly bump into a servant boy who is described as a "husky youth." This is Adam and he is responsible for stealing the money that Widge has carefully saved and packed away in his belongings, or so Widge suspects. Note how Widge reacts to Adam's thievery:
Though I was sure it was the stableboy's doing, I knew better than to say so. I was the new boy here, and I had long since learned that new boys have no rights. I would have to content myself with cursing him roundly and silently.
Adam is therefore superior to Widge in that he is not a "new boy" and he is clearly also larger and stronger than Widge. He is able to use his superior knowledge of city life and his position of stableboy in this house to his advantage, as it allows him to prey on weaker characters such as Widge who are rather naive and powerless.