The irascible Kai, the vice-captain of the law enforcement team in Stephanie was one of the six apostles in the red windmill along with Emma and Jiang yuanchi. However, he had entered the six apostles much earlier than the two of them and was the law enforcer that the trouble-making Wizards were most afraid of.
According to Roger, Kai was actually a good person, but he liked to use violence in the process of enforcing the law, which was opposed by the Wizards. On the surface, the law enforcement team was there to restrain some of the lawless Wizards, but in fact, it was more to protect the interests of the Wizards.
This guy's life in the law-enforcement team was also quite rough. It could be said that he had entered and exited several times, and had experienced many setbacks. He had recently re-assumed his position, perhaps to deal with the turbulent undercurrents in the increasingly complicated Stephanie San.