Xing Ke is the official who granted the Knights amnesty in the Chinese embassy. He also promised to get the empress out of the forbidden city.
His coup d'etat failed when Zero showed up, but the eunuchs are willing to use him.
His tactical genius forces Zero onto his back foot.
Xing Ke has captured Kallen and has Zero trapped. Unfortunately for him, the Eunuchs use their international relations to call in a favor from the Knights of the Round: destroy both the rebels and the Japanese!
Xing Ke is drawn into a hopeless position when the empress gets out.