King Zhaoxiang of Qin
Reigning over 55 years, he was one of the longest-serving rulers during the Eastern Zhou Dynasty. Although making numerous policy mistakes during his later years, his aggressive territorial expansions were pivotal in consolidating the state of Qin as the dominant military powerhouse in the late Warring States period. It was the strategic dominance established during his reign that paved the way to Qin's eventual successful unification of China under his great-grandson, Ying Zheng.
Qin Er Shi
In 207 BC, the Qin dynasty collapsed fifteen years after its establishment. A son of Fusu (allegedly; there is no firm consensus on what his relationship to the Qin royal family really is), Ziying (子婴), was made "king of Qin state", a reduced title. Ziying soon killed Zhao Gao and surrendered to Liu Bang one year later.