Alain Delon was originally attached but pulled out due to his dissatisfaction with the script. The producers then suggested Johnny Hallyday, whom Johnnie To had never heard of.

Third part of an informally established trilogy, with 'The Mission' (1999) and 'Exiled' (2006) being the previous installments. Among sharing a number of noted cast members (Anthony Wong, Simon Yam, Lam Suet) and locations (Macau), the films are primarily connected by certain ideas, such as - at times ironical - reflections on themes like brotherhood and loyalty; fatalism; and group dynamics. All three films also feature elaborate action sequences with a strong, almost geometrical sense of space.

Johnny Hallyday's character shares the same name as Jack Nicholson's character from The Departed. The only slight difference being the French "Francois Costello" instead of "Frank Costello".