Zeng Sai the Tree that Defies the Fire is an ancient warlord of the Horselords.
- "Of all threats the young Jade Empire faced, the greatest was the barbarian warlord Zeng Sai. Titled "The Tree that Defies the Fire," Zeng Sai managed to organize the barbaric Horselords into an efficient and deadly machine of warfare, conquering much of the lands to the west and north of the Empire before coming to bear on the borders of the Jade Empire itself. Zeng Sai, whose savagery denied even the great Wall built to keep his people out, led his hungry, maddened people to attack our fledgling Empire in a rabid attempt to destroy all that would become our advanced and prosperous civilization.
- So vicious and deadly was Zeng Sai's attack that it roused the insular Spirit Monks from their temple in the Land of Howling Spirits to come to the Empire's aid. Left unconquered by the devouring Horselord army, the monks of Dirge stood alongside the Empire and, in a great battle recounted by sages, playwrights, and scholars around the known world, laid waste to Zeng Sai and his ravenous army of wild bowmen. With the help of the monks from Dirge, the Empire finally burned down the Tree that Defies the Fire."
- –The Undeniable Fire, scrollstand located in the Lotus Assassin Fortress.
The Player character meets the ghost of Zeng Sai in the deep tombs of of the Lotus Assassin Fortress. According to Sagacious Zu, the deep tombs hold malevolent spirits from a time when the Jade Empire nearly fell. Chaotic and powerful, they hunger for revenge. The ghost of Zeng Sai relished the pain and chaos of the living and fights the player character because they are a spirit monk and also because they brought peace and order. After defeating Zeng Sai, Sagacious Zu advises to take Zeng Sai's body from his grave and use it for the Lotus Assassins' soul extractor. The pure chaos of Zeng Sai's spirit shard will cripple the assassins' Jade Golem and those it commands.
Immune to weapon styles.
- Zeng Sai has the same appereance as Strangler Jizu in the mines of the Quarry.
- In summmer video Zeng Sai was the name of Black Whirlwind.