Who is Takumi from Looking for Alaska and what is their importance?

Japanese student Takumi attends the same school as Miles, Chip and Alaska. He, like Miles, is a follower rather than a leader. While his reasons for hanging out with Chip and Alaska are never fully defined, there is the sense that he feels like something of an outsider at the school, and hangs out with them because he makes them feel more welcome than the other students. Like Miles and Chip, he blames himself for Alaska's death, but there is the sense that, UN-like Miles and Chip, he doesn't really come to terms with either what happened or his sense of responsibility.