Kingdom, Vol. 4 (manga)

Ying Zheng's surprise attack to reclaim the throne has begun. While he and a number of his own men, along with the Mountain People, keep attention on themselves at the steps of the palace, the real attack is underway, with Xin leading a separate force of Diao, Bi, a few Qin soldiers, and more Mountain People through an escape tunnel with a direct route to the throne room. Their goal? Put an end to Cheng Jiao and remove him from the throne while the main force acts as a distraction. But Cheng Jiao is prepared and not going down without a fight, and soon Xin's team is met with monstrous foes!