King Zhaoxiang of Qin
In 306 BC, the young King Zhaoxiang ascended to the throne, with his mother Queen Dowager Xuan serving as regent. Knowing Qin could not focus on eradicating Yiqu when it had the hostile eastern states to deal with, and her son's rule was still shaky due to numerous rival princes keen to capture the throne, Queen Dowager Xuan decided to use an approach of pretended conciliation. She invited the king of Yiqu to live long-term in the Ganquan Palace, and consummated a seductive liaison that produced two sons with him. This completely removed the Yiqu King's hostility towards Qin, as the beguiled king had lost all cautiousness around the Queen Dowager. At the same time, King Zhaoxiang was aggressively acting to weaken rival warring states in the east and south, and Queen Dowager Xuan was secretly planning with her son the eventual annihilation of Yiqu.
King Min of Qi
In 288 BC. King Min took the title of Di of the East (東帝), and his ally King Zhaoxiang of Qin called himself Di of the West (Di was originally the name of the high god of the Shang. It also (or later) had a weaker sense of sacred or divine; the same character was used to mean Emperor in later times.) But so many people objected that both kings were forced to return to the title of "king" (wáng 王) and there was no Di in China until Qin Shi Huang unified China in 221 BC and gave himself the title of Huang Di, which we translate as Emperor.