Question: Who is Chey Chettha Iii's paternal grandfather?

Knowledge 1: Chey Chettha III
Chey Chettha III (1639–1673) or Batom Reachea II was a Cambodian king during the Dark ages of Cambodia.He reigned from 1672 to 1673.Chey Chettha III was the only son of Batom Reachea.In 1671, he became the son-in-law of his uncle, King Barom Reachea V, by marrying his eldest daughter, Princess Sri Thida Kshatriyi.In December 1672, he murdered his father-in-law and seized the throne, and forced his cousin Bhagavatti Dav Kshatriyi (also the wife of his uncle Prince Ang Tan) to be his wife.Chey Chettha III was assassinated by the Chams and Malays in the employ of his wife, Gama Kshatriyi, just five months after his coronation, in April (or May) 1673. [SEP] Knowledge 2: Batom Reachea
Batom Reachea (born Ang Non ; 1616–1642) was King of Cambodia from 1640 to 1642.Ang Non was the eldest son of the "uprayorach" (ឧភយោរាជ, "Great Joint King")Outey.Ang Non married Princess Ang Na Kshatriyi, whom was the daughter of King Chey Chettha II and his Vietnamese spouse Neak Ang Chov .King Ang Tong Reachea died in 1640.Although Ponhea Chan should be the next king, Outey forced Chan to give the crown to Ang Non.Chan was dissatisfied.With the help of Cham and Malay mercenaries, Chan assassinated Outey on 5 January 1642.In the same time Batom Reachea was away on a hunting trip.Chan captured him and had him executed in Oudong.
Knowledge 1: Chey Chettha III
Chey Chettha III (1639–1673) or Batom Reachea II was a Cambodian king during the Dark ages of Cambodia.He reigned from 1672 to 1673.Chey Chettha III was the only son of Batom Reachea.In 1671, he became the son-in-law of his uncle, King Barom Reachea V, by marrying his eldest daughter, Princess Sri Thida Kshatriyi.In December 1672, he murdered his father-in-law and seized the throne, and forced his cousin Bhagavatti Dav Kshatriyi (also the wife of his uncle Prince Ang Tan) to be his wife.Chey Chettha III was assassinated by the Chams and Malays in the employ of his wife, Gama Kshatriyi, just five months after his coronation, in April (or May) 1673. [SEP] Knowledge 2: Chey Chettha II
Chey Chettha II( 1576 – 1628) was a king of Cambodia who reigned from Oudong, about 40 km northwest of modern- day Phnom Penh, from 1618 to 1628.He was the son of King Srei Soriyopear( r. 1603- 1618).He is noted for moving the royal capital from Srei Sonthor to Oudong, and for his cooperation with the Nguyễn Lords of Vietnam against the Siamese, which led to the Vietnamese annexation of the Mekong Delta, including the city of Prey Nokor — the precursor of modern- day Ho Chi Minh City.In order to balance the influence of the Siamese forces, which had devastated the previous capital at Lovek during the reign of his father, Chey Chettha approached the Nguyễn lord for help.To cement the resulting alliance, Chey Chettha was married to Princess Nguyễn Phúc Ngọc Vạn, a daughter of Lord Nguyễn Phúc Nguyên, in 1618.In return, the king granted the Vietnamese the right to establish settlements in Mô Xoài( now Bà Rịa), in the region of Prey Nokor — which they colloquially referred to as" Sài Gòn", and which later became Ho Chi Minh City.In 1623, Chey Chettha allowed the Vietnamese to set up a custom house at Prey Nokor, in order to collect taxes.This settlement was the start of a major expansion by the Vietnamese beyond the borders established by Lê Thánh Tông in 1471.The increasing waves of Vietnamese settlers which followed overwhelmed Chey Chettha II's kingdom — weakened as it was due to war with the Siamese—and slowly Vietnamized the Mekong Delta area, claiming it for their own in the 1690s.The Dutch East India Company established ties with Cambodia in 1620, during Chey Chettha's reign; in 1623, they established an outpost at Kompong Luong, a riverside port near Oudong.
Knowledge 1: Chey Chettha III
Chey Chettha III (1639–1673) or Batom Reachea II was a Cambodian king during the Dark ages of Cambodia.He reigned from 1672 to 1673.Chey Chettha III was the only son of Batom Reachea.In 1671, he became the son-in-law of his uncle, King Barom Reachea V, by marrying his eldest daughter, Princess Sri Thida Kshatriyi.In December 1672, he murdered his father-in-law and seized the throne, and forced his cousin Bhagavatti Dav Kshatriyi (also the wife of his uncle Prince Ang Tan) to be his wife.Chey Chettha III was assassinated by the Chams and Malays in the employ of his wife, Gama Kshatriyi, just five months after his coronation, in April (or May) 1673. [SEP] Knowledge 2: Chey Chettha IV
Chey Chettha IV( 1656–1725), born Ang Sor, was a Cambodian king during Dark ages of Cambodia( r. 1675–1695, 1696–1700, 1701–1702, 1705–1706).He was the second son of Barom Reachea V( or Barom Reachea VIII) and also a younger brother of Kaev Hua II.Vietnamese army attacked Phnom Penh, the king Kaev Hua II fled into forest.Ang Sor surrendered to Vietnamese.He was crowned the Cambodian king by Vietnamese, while Ang Nan( Padumaraja III) was crowned the vice king( uparaja).Chey Chettha IV occupied Longvek, Padumaraja III occupied Prey Nokor( Saigon).Both of them paid tribute to Vietnamese Nguyễn lord.In 1688, Dương Ngạn Địch, a Chinese adventurer and also a general of Nguyễn lord, was murdered by Hoàng Tiến( 黃進).Hoàng Tiến occupied Mỹ Tho and revolted against Nguyễn lord.Hoàng Tiến also attacked Cambodia.Using this excuse, Chey Chettha IV started to building fortifications and did not pay tribute to Nguyễn lord.In the same year the rebellion was put down, Chey Chettha had to pay tribute like before.Chey Chettha IV abdicated in favour of his sonOutey I in 1695.In the next year Outey I died, Chey Chettha IV restored.Nguyễn Hữu Cảnh was sent to Saigon by Nguyễn lord to expand his southern territory.It violated Cambodia's advantages; Chey Chettha IV tried to drive them out, however, he was defeated.In 1700, Vietnamese army captured Phnom Penh.The vice king( uparaja) Ang Em( Barom Ramadhipati) surrendered to Vietnamese, and ascended the throne.Chey Chettha IV surrendered in the next year, he was allowed to restore.Chey Chettha IV abdicated in favour of his son Thommo Reachea III in 1702.Chey Chettha IV then married a daughter to the vice king Ang Em. But, Thommo Reachea III drove out Ang Em with the help of Ayutthaya Kingdom.Ang E m fled to Saigon, in there he was supported by Nguyễn lord.A Vietnamese army under Nguyễn Cửu Vân( 阮久雲) invaded Cambodia again.Thommo ReacheaIII fled to Ayutthaya Kingdom.Ang E m came back to Cambodia and lived in Longvek.Chey Chettha IV was installed as the king by Vietnamese.He abdicated in 1706, and Thommo Reachea III crowned the king again.With the help of Ayutthaya Kingdom, Thommo Reachea III came back to Cambodia, and captured Longvek in 1714.A Vietnamese army under Trần Thượng Xuyên and Nguyễn Cửu Phú( 阮久富) was sent to Cambodia to help Ang Em.They besieged Longvek.Chey Chettha IV and Thommo Reachea III were forced to flee to Ayutthaya Kingdom.

Answer: Outey