Age: 16-17
Ei Sei is the king of Qin who bears a striking resemblance to Shin's friend Hyou. His father was the late king, but his mother did not have any royal blood.
Ei Sei seems level headed but somewhat cold. When Shin was going to let Jo Kan leave, Ei Sei kills the assassin without remorse. However, he does care at least a little bit about those loyal to him.