|Affiliation||Hong Kong Triad|
|Manga||Chapter 48: El Baile de la muerte Part 2|
|Anime||Episode 25: Collateral Massacre|
|Japanese Anime Voice||Chikara Ousakaa|
|English Anime Voice||Michael Adamthwaite|
Biu Yuen is a member of the Hong Kong Triad, who first appears in Chapter 48 of the manga, and the OVA of the anime. He works for Mister Chang, although appears to be a new addition to the Roanapur branch of the Triad, and/or skeptical of Chang's abilities.
Biu Yuen was first seen in the OVA, Roberta's Blood Trail. He works for Chang, although does not appear to be particularly loyal to or respectful of him. He openly says that he "didn't understand why the Dailo chose to elevate someone like [Chang]," and refers to him as a "dirty cop who killed his partners." However, after seeing how Chang handled Rock and the situation with Roberta in the OVA, he seems convinced of his ability.
Biu Yuen seems cocky, and disrespectful to Chang. In a notable contrast to Chang, he has no respect for Balalaika, calling her a "Russian battleaxe," and commending Chang for the way he manipulated her. He appears not to know Chang at all, which suggests he might be a new addition to Roanapur. Chang and Balalaika have a business relationship built on "profit and trust," which makes it unlikely that Chang manipulated her, and more likely that they worked together to preserve their joint interest, the city of Roanapur.
- In a popularity contest during the 10th collection manga release, Biu Yuen ranked 5th with 894 votes