Black Whirlwind is a mercenary formerly hired by Lord Yun who joined the Player as a follower. Black Whirlwind grew up in an abusive household until he killed his father. After his father's death his mother kicked him out onto the streets. He was once a champion at the Imperial Arena but left shortly after his brother Raging Ox's death. Black Whirlwind is a brawler of legendary stature, although the legends dwell as much on his drunken stupidity as his skill in combat. He is rude, crude and thickheaded, so much so that he has simply no understanding of what he can and cannot do. While he is an absolute disaster at anything diplomatic, if someone is needed to survive a suicidal battle against overwhelming odds, Black Whirlwind is the man for the job.
The Black Whirlwind accepted a job hunting demons for the Celestial Bureaucracy, but the ensuing red tape frustrated him so much that he gave up and made for the Mysterious East. Shortly thereafter, the Empire received a great influx of Outlanders, many of whom were missing limbs and other body parts. He returned to the Jade Empire several years later, but this time he came from the west. He couldn't explain how he did it, but he was the only person unsurprised to arrive back where he started. Expressing a newfound hatred for a people who couldn't make a decent bowl of wine, the Black Whirlwind vowed to never again leave the Jade Empire. A week later, he got bored and headed off to the north.
Spear Catches Leaf: "You've just had the... unexpected honor of defeating the Black Whirlwind, the self-styled deadliest mercenary in the Jade Empire".
Player: "What earns a mercenary a title like "deadliest?""
Spear Catches Leaf: "The tales say this man once stormed an entire fortress alone, naked, and screaming his defiance into the night".
The Black Whirlwind: "Ha! Scared the tar out of those border guards! But they botched the story; I was naked, screaming, *and* I was dead drunk".
- –Conversation between Spear Catches Leaf, the Player and the Black Whirlwind
- The Black Whilrlwind: "I wont stop until they are ankle deep in blood, Head first".
In summer demo his name was Zeng Sai.