Cast
RZA as Blacksmith / The Man with the Iron Fists:
An emancipated slave from America who becomes the blacksmith of Jungle Village. He channels an ancient energy to turn himself into a living weapon. His name is Thaddeus Henry Smith. RZA wrote the role specifically for himself, and trained in Hung Ga for 1–2 hours a day over 2 months in preparation.
Rick Yune as Zen-Yi, The X-Blade:
The son of the murdered Lion Clan leader who goes to Jungle Village to avenge his father's death. RZA said that he had Yune in mind for the role before the script had been completed.
Russell Crowe as Jack Knife:
An opium-addicted British soldier named after his signature weapon. The character was partly inspired by RZA's late cousin Ol' Dirty Bastard. Crowe based his performance on Clint Eastwood in Dirty Harry (1971) and The Outlaw Josey Wales (1976). Crowe agreed to join the cast because of his previous working relationship with RZA. Crowe was only able to spend 10 days filming his scenes.
Lucy Liu as Madam Blossom:
The owner of the Pink Blossom brothel, whom Liu described as the queen of the village. Liu wanted to emphasize Blossom's strength against all the male fighters and convinced RZA to give the character a fight sequence with Cung Le's Bronze Lion.
David Bautista as Brass Body:
A mercenary capable of turning his body to metal, making him invulnerable. Bautista described the character as a "good guy" who "made a lot of bad choices in his life. He doesn’t really understand the difference between right and wrong." RZA auditioned Bautista for the role after seeing him "moving as fast as lightning" during a stick-fighting training video.
Jamie Chung as Lady Silk:
A prostitute in the Pink Blossom and the blacksmith's lover.
Cung Le as Bronze Lion:
A member of the Lion Clan. Le came to RZA's attention following his 2008 mixed martial arts fight against Frank Shamrock. Bronze Lion's fighting style incorporates elements of Tiger Kung-Fu and Le's own training in kicks and scissor kicks.
Byron Mann as Silver Lion:
The leader of the Lion Clan after he kills the previous leader. Mann was initially cast for a smaller role but after his successful audition, he was given the bigger role of Silver Lion.
The cast also includes Pam Grier as the blacksmith's mother Jane, Osric Chau as Blacksmith's assistant, MC Jin as Zen-Yi's ally Chan, Daniel Wu as Poison Dagger, and Andrew Lin and Grace Huang as The Geminis. Co-writer Eli Roth appears in a cameo. Several veteran martial arts actors—including Chen Kuan-tai as Golden Lion, Bryan Leung as Hyena Chief, Telly Liu as Iron Lion, Xue Jing Yao as Copper Lion, Zhu Zhu as Zen-Yi's fiancée Chi Chi, Terence Yin as the Governor, and Gordon Liu as The Abbot—appeared in the film. Liu's role was written for RZA's Shaolin teacher Shi Yan Ming, but Ming could not obtain permission to return to China for filming.