Alexie develops his characters as a way to address main ideas in The Absolutely True Diary of a Part-Time Indian.
Junior is an example of how Alexie addresses main ideas through characters. For example, Junior is used to address the main idea of identity, or who a person is and what they believe. He represents the idea of identity both on the Rez and off it at Reardan. Junior shows the challenges he experiences forming his identity when he feels out of place on the Reservation. Junior strives to be something more than the people around him. This is a part of his identity. When Junior goes to Reardan and is the only Native American, the main idea of identity is seen in a different context. Junior has to address identity while being intimidated and seen as "different." In both settings, Alexie uses Junior as the way to address the main idea of identity formation.
Characters are used again when Alexie wants to address the main idea of loss. Rowdy deals with loss through anger and bitterness. The Native Americans that gather for Junior's grandmother's funeral are another set of characters who address the main idea of loss. They celebrate and honor through laughter the memory of one who meant so much to them. Junior's father is another way in which loss is addressed. He internalizes his pain through alcohol. His sad eyes reflect a deep reservoir of hurt that has been embedded within his psyche. In these instances, Alexie is able to use characters to address main ideas in his novel.