Who is Danny Hupfer from The Wednesday Wars and what is their importance?

Danny Hupfer is also in the seventh grade and is a friend of Holling's. Danny is a good friend, although there are times he, like other students, is less than nice. It is Danny who threatens Holling when he fails to provide cream puffs, as promised, to the class, but it is also Danny who stands up for Holling when Mickey Mantle refuses to sign his baseball. Danny even goes so far as to give his ball back, showing his support for Holling. As a reward, Mrs. Baker allows Danny to participate in an afternoon of baseball with two Yankee players in an effort to make up for their distress at the hands of Mantle, their hero. Danny is also a caring person for his other friends. When students make fun of Mai Thi for her upbringing in Vietnam, it is Danny who comes to her rescue, punching the boy tormenting her.