Mafia: Millefiore Family/Vongola Family
Flame Attribute: Sun
Ambitions: To become a Musician
Shouichi is part of the Millefiore Family and is captain of the White Spell 2nd Rose Squad, and one of the six A rank members in the Millefiore. It seems that Byakuran and Shouichi have a somewhat close relationship; Byakuran calls Shouichi "Shou-chan" and seems to trust him the most. He is currently involved in some very important research for the family.
However it turns out later in the series he is really on the Vongola side, sent by the 10-years-in-the-future Tsuna to infiltrate the Millifiore family and bring Tsuna and his friends to the future in order so that they may be trained to take down Byakuran.