Duke Gong of Qin
Duke Gong of Qin (died 604 BC) was from 608 to 604 BC the sixteenth ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty.
His ancestral name was Ying (嬴), and Duke Gong was his posthumous title.
Duke Gong succeeded his father Duke Kang of Qin, who died in 609 BC, as ruler of Qin.
He reigned for five years before dying in 604 BC.
He was succeeded by his son, Duke Huan of Qin.
Duke Cheng of Qi
Duke Cheng of Qi (died 795 BC) was from 803 to 795 BC the eleventh recorded ruler of the State of Qi during the Western Zhou Dynasty of ancient China.
His personal name was Lü Yue (呂說), ancestral name Jiang (姜), and Duke Cheng was his posthumous title.
Duke Cheng succeeded his father Duke Wen of Qi, who died in 804 BC, as ruler of Qi.
He reigned for 9 years and died in 795 BC.
He was succeeded by his son, Duke Zhuang I of Qi.
Duke De of Qin
Duke De of Qin (710–676 BC) was from 677 to 676 BC the eleventh ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty.
His ancestral name was Ying , and Duke De was his posthumous title.
Duke De was the second of the three sons of his father Duke Xian of Qin.
His younger half-brother Chuzi was the first to succeed Duke Xian in 704 BC, but was killed six years later.
His older brother Duke Wu of Qin then ascended the throne and reigned for 20 years.
Although Duke Wu had a son named Bai (白), when he died in 678 BC it was Duke De who succeeded him, while Prince Bai was enfeoffed at the capital Pingyang.
In the first year of his reign, Duke De moved the capital to Yong (in present-day Fengxiang, Shaanxi), which would remain the capital of Qin until almost three centuries later, when Duke Xian (Shixi) moved the capital to Yueyang (櫟陽) in 383 BC.
However, Duke De reigned for only two years before dying in 676 BC, aged 34.
He had three sons, who would in turn ascend the throne as Duke Xuan, Duke Cheng, and Duke Mu, respectively.
Chuzi II
Chuzi( 389 BC or 388–385 BC) was from 386 BC to 385 BC the 28th ruler of the Zhou Dynasty Chinese state of Qin that eventually united China to become the Qin Dynasty.
His ancestral name was Ying( 嬴), and Chuzi was his posthumous name.
He was the second of two child rulers of Qin called Chuzi.
He is also variously referred to as Duke Chu of Qin( 秦出公), Shaozhu of Qin( 秦少主), or Xiaozhu of Qin( 秦小主)( Shaozhu and Xiaozhu both mean" Young Lord").
Chuzi was the grandson of Duke Jian of Qin, who was the uncle of his predecessor Duke Ling.
When Duke Ling died in 415 BC, the throne passed to his uncle Duke Jian instead of to his son, the later Duke Xian.
Duke Jian reigned for 15 years and was succeeded by his son, Chuzi's father Duke Hui II, who reigned for 13 years and died in 387 BC.
When Chuzi succeeded his father as ruler of Qin he was either one or two years old, and the state of Qin was effectively controlled by his mother, the duchess dowager.
Just two years later, in 385 BC a minister in the government, Jun Gai( 菌改), rebelled against Chuzi and the duchess.
He led his forces to escort Duke Xian, who was at the time exiled in the State of Wei, back to Qin, killed Chuzi and his mother and installed Duke Xian on the throne.
Chuzi was just three or four years old when he died.
Duke Xuan of Qin
Duke Xuan of Qin( died 664 BC) was from 675 to 664 BC the twelfth ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty.
His ancestral name was Ying, and Duke Xuan was his posthumous title.
Duke Xuan was the eldest of the three sons of his father Duke De of Qin, and succeeded his father as ruler of Qin when Duke De died in 676 BC, aged 34.
He reigned for 12 years and died in 664 BC.
Although Duke Xuan had nine sons, he passed the throne to his younger brother Duke Cheng of Qin, who would in turn pass the throne to the third brother Duke Mu of Qin.
Li Fengji
Li Fengji( 758 – February 27, 835), courtesy name Xuzhou( 虛舟), formally Duke Cheng of Zheng( 鄭成公) or Duke Cheng of Liang( 涼成公), was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reigns of Emperor Xianzong, Emperor Xianzong's son Emperor Muzong, and grandson Emperor Jingzong.
He was portrayed by traditional accounts as full of machinations against his political opponents.
Marquis of Qin
The Marquis of Qin( died 848 BC) was the second ruler of the ancient Chinese state of Qin, founded when his father Feizi was granted a small fief at Qin by King Xiao of Zhou.
The Marquis of Qin succeeded his father, who died in 858 BC, and ruled for 10 years.
He died in 848 BC and was succeeded by his son Gongbo.
His ancestral name was Ying, but his given name is not known.
Although Qin would eventually develop into a major power that would conquer all other Chinese states and unite China in 221 BC to start the Qin Dynasty, at the time of the Marquis of Qin it was still a minor state of the Western Zhou Dynasty classified as an" attached state"( 附庸," fuyong").
Qin rulers did not receive any nobility rank until four generations later during the reign of Duke Xiang of Qin, so" the Marquis of Qin" was presumably an honorific posthumous title that his descendants used to refer to him.
King Huiwen of Qin
King Huiwen of Qin( 356–311 BC), also known as Lord Huiwen of Qin or King Hui of Qin, given name Si( 駟), was the ruler of the Qin state from 338 to 311 BC during the Warring States period of Chinese history and likely an ancestor of Emperor Qin Shi Huang.
He was the first ruler of Qin to style himself" King"( 王) instead of" Duke"( 公).
Duke Cheng of Jin
Duke Cheng of Jin (died 600 BC) was from 606 to 600 BC the ruler of the State of Jin, a major power during the Spring and Autumn period of ancient China.
His ancestral name was Ji, given name Heitun, and Duke Cheng was his posthumous title.
He was the youngest son of Duke Wen of Jin, and succeeded his nephew Duke Ling of Jin, when Zhao Dun and Zhao Chuan killed Duke Ling and installed Heitun on the throne.
During the seven years of Duke Cheng's reign Jin attacked the states of Zheng, Chu, Qin, and Chen.
Duke Cheng died in 600 BC and was succeeded by his son Duke Jing of Jin.
Duke Cheng of Qin
Duke Cheng of Qin (died 660 BC) was from 663 to 660 BC the thirteenth ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty.
His ancestral name was Ying , and Duke Cheng was his posthumous title.
Duke Cheng was the second of the three sons of his father Duke De of Qin.
His older brother Duke Xuan of Qin succeeded his father as ruler of Qin in 676 BC.
But when Duke Xuan died in 664 BC, he passed the throne to Duke Cheng instead of one of his nine sons.
When Duke Cheng died four years later, he did the same and passed the throne to the third brother Duke Mu of Qin, even though he had seven sons.

Question: Who is the paternal grandfather of Duke Cheng Of Qin?
Answer: Duke Xian of Qin