Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
Henry Bryant (naturalist)
Henry Bryant( May 12, 1820 – February 2, 1867) was an American physician and naturalist.
He was the grandfather of Henry Bryant Bigelow.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Prithvipati Shah
Prithvipati Shah( ?–1716) was the king of the Gorkha Kingdom in the Indian subcontinent, present- day Nepal.
He was the grandfather of Nara Bhupal Shah.
Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Fujiwara no Nagara
, also known as Fujiwara no Nagayoshi, was a Japanese statesman, courtier and politician of the early Heian period.
He was the grandfather of Emperor Yōzei.
Abaqa Khan
Abaqa Khan (1234–1282, , "paternal uncle", also transliterated Abaġa), was the second Mongol ruler ("Ilkhan") of the Ilkhanate.
The son of Hulagu Khan and Lady Yesünčin.
He was the grandson of Tolui and reigned from 1265 to 1282 and was succeeded by his brother Tekuder.
Much of Abaqa's reign was consumed with civil wars in the Mongol Empire, such as those between the Ilkhanate and the northern khanate of the Golden Horde.
Abaqa also engaged in unsuccessful attempts at military invasion of Syria, including the Second Battle of Homs.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Oljath
Oljath (Öljätäi)  was a Queen consort of Georgia as the wife of two successive kings, Vakhtang II (r. 1289–1292) and David VIII (r. 1292–1311).
She was a daughter of Abaqa Khan, the Mongol Ilkhan of Iran.

Question: Who is the paternal grandfather of Oljath?
Answer: Hulagu Khan