At about four years old, Ulysses is Homer's younger brother, while Marcus, in his late teens, is the oldest of the three Macauley sons. Both play important roles in Homer's life, with Homer feeling responsibility for Ulysses alongside a profound responsibility to Marcus. Both brothers play important roles in shaping Homer's life and journey of transformation. Ulysses is a much more active presence in Homer's life, an actual physical presence - in other words, Ulysses is there, sometimes causing trouble, often creating complication, generally triggering affection. Marcus, on the other hand, is physically absent but more emotionally present - the responsibility triggered by his absence is constantly in Homer's mind. Marcus generally triggers inspiration, often awakens admiration, and on one notable occasion at the end of the book, is the catalyst for redemption, for both his friend Tobey George and the rest of his family. Meanwhile, it's interesting to note that on some level, Ulysses and Marcus are more alike each other than they are to Homer.