If Riboku isn't dead I predict he and the royal family will defect to Qin. In the Riboku spin-off i'm pretty sure he was in a nation that wasn't Zhao so I don't think he has much loyalty to Zhao. I don't know why he was serving the previous Zhao king but with the new one wanting him dead and Riboku himself saying the crown prince has no chance of succession they have no chance of survivning if they return to zhao. Ei Sei wants to unify China so I feel like Riboku who seems to be devoted to the nation he serves would be a valuable asset. This is pure speculation I don't want to google the actual history to find out what happens.
