In the novel and manga, Boy #2 Keita Iijima is a loner who is a former friend of Shinji Mimura. The two have had a falling out, due to Keita's spite in refusing to help fight street gang harassing Shinji.
When Keita wishes to join Yutaka Seto and Shinji, Shinji points a gun at Keita and tells him to leave. Shinji fires the gun in an attempt to scare him off, but accidentally hits and kills him. This begins a chain of events which leads to the ultimate failure of Mimura's plan. In the film, Iijima is Mimura's friend, and he travels with Mimura and Yutaka. In the end Kazuo Kiriyama kills Iijima and Yutaka.