Shuusei is the jokester of the group and likes to make fun of people on a regular basis. He enjoys portable video games and spends most of his free time playing them. However, he is more serious when he's on the job. He hates people who take the freedom they have for granted, because of the fact that he's been excluded from society since he was five years old.

Spoiler

Later on in the series, he is killed by the Chief because he saw the true form of Sibyl System, and has been reported missing ever since.