Alexie constructs Junior's narrative as one where nearly every character impacts Junior's life. Every character has some type of altering impact on his life and his being. Each character can have an argument made as to how their impact on Junior's life is profound. His father represents the blighted hope of what could be, as does Junior's sister, who could have been a writer. Junior's grandmother represents the cultural pride that is so much a part of his identity. Penelope represents what can be and what he hopes could be.
Yet, I think that Rowdy holds the most impact and develops the most profound impact on Junior. Rowdy is the character that represents Junior's life as a Native American in the way he stands up for him and in the torment that is such a part of Rowdy's being. Junior recognizes in Rowdy someone as, if not more, tormented than himself at his condition of being in the world. When Junior leaves and goes to Reardan, Rowdy being left behind leaves an impact on him. It represents how Junior will be a part of both worlds. In this, Rowdy represents the Native American half of Junior's identity. It is akin to a shadow, something that cannot be escaped. When Junior plays basketball against Rowdy at the end of the narrative without keeping score, it represents how Junior's identity will consist of multiple ends, differing ends of the spectrum of his experience.