Takeshi Yamamoto, addressed as "Yamamoto" by almost everyone in the series, has a warm and friendly personality and is rarely seen not smiling. He is, however, very naive. Yamamoto is the type of character that can make friends with everyone. However, Yamamoto can become angry when his friends are hurt or injured. He is also willing to sacrifice things important to him to save his friends from danger. He is a fairly-tall teenager with short, spiky black hair and large brown eyes. Despite his easy-going personality, Yamamoto has shown that he has hidden talent as a hitman.