Alexander of Trebizond
Alexander Komnenos or Skantarios Komnenos was a co-emperor of the Empire of Trebizond, first with his father Alexios IV of Trebizond then, after several years in exile, with his brother John IV.
Irene of Trebizond
Irene of Trebizond( died around 1382) was the bigamous wife of Basil of Trebizond, by whom he had two sons, Alexios and John( later Alexios III of Trebizond), and possibly three daughters Anna, Maria and Theodora.
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.
Rusudan of Georgia, Empress of Trebizond
Rusudan of Georgia, Empress of Trebizond was a consort of Manuel I of Trebizond, and the mother of Empress Theodora.
Very little is known for certain about her.
Helena Kantakouzene, Empress of Trebizond
Helena Kantakouzene( died 1463) was the second wife of David of Trebizond, the last Emperor of Trebizond.
Recent research has led to doubts regarding her existence.
Eudokia of Trebizond
Eudokia Megale Komnene (died after 4 September 1395), was a Trapezuntine noblewoman and a member of the powerful Byzantine Komnenos dynasty as a daughter of Emperor Alexios III of Trebizond.
She was styled "Despoina in Sinop" after her first marriage to Muslim Turkmen Tadjeddin Pasha of Sinop, Emir of Limnia, which had been arranged by her father to foster peaceful relations between the Pontic Greek Christians and the neighbouring Muslims.
Alexios IV of Trebizond
Alexios IV Megas Komnenos or Alexius IV( 1382–1429), Emperor of Trebizond from 5 March 1417 to October 1429.
He was the son of Emperor Manuel III and Gulkhan- Eudokia of Georgia.
Alexios III of Trebizond
Alexios III Megas Komnenos (5 October 1338 – 20 March 1390), or Alexius III, was Emperor of Trebizond from December 1349 until his death.
He is perhaps the best-documented ruler of that country, and his reign is distinguished by a number of religious grants and literary creations.
He was the son of Emperor Basil of Trebizond and his second (and bigamous) wife, Irene of Trebizond.
Alexios III was originally named John (Ιωάννης, "Iōannēs"), and took the name Alexios either in memory of his older brother who had died prematurely or of his paternal grandfather, Emperor Alexios II of Trebizond.
His personal appearance was described by George Finlay as "extremely noble".
Finlay contributes the following details: "He was florid, blonde, and regular-featured, with an aquiline nose, which, his flatterers often reminded him, was considered by Plato to be a royal feature.
In person he was stout and well formed; in disposition he was gay and liberal; but his enemies reproached him with rashness, violence, and brutal passions."
Maria of Gothia
Maria of Gothia was the first wife of David of Trebizond, last Emperor of Trebizond, whom she married in 1426.
Pankratios of Trebizond
Pankratios or Pangratios was the first Metropolitan bishop of Trebizond following the Ottoman conquest of the Empire of Trebizond in 1461.
Nothing is known about Pankratios' origin or early career prior to his appointment as metropolitan.
The see had been vacant since the capture of Trebizond and the incorporation of the Empire of Trebizond to the Ottoman Empire in 1461, as the bulk of the Trapezuntine upper classes, including the secular nobility and the ecclesiastical hierarchy, were transferred to the Ottoman capital, Constantinople.
It was not until ca. 1472 that the vacancy was addressed.
This was partly the result of the appointment of the Trapezuntine Symeon I as Patriarch of Constantinople, but owed more to political considerations on the part of the Ottoman Sultan, Mehmed II: the Christians of the Pontus region around Trebizond had been restive against Ottoman rule, and were encouraged by the neighbouring Aq Qoyunlu sultan Uzun Hassan.
The latter was linked through family ties with the former imperial house of Trebizond, and lent his support to a scion of that house, Alexios Komnenos.
In order to counteract the threat of a rebellion, the Sultan elevated Symeon to the patriarchal throne, and he immediately appointed Pankratios to the metropolitan throne of Trebizond.
It appears, however, that the latter was unable to satisfy the Sultan's expectations about calming the province, and already after a few months Mehmed II demanded his replacement.
Pankratios was succeeded by Dorotheos II, and nothing further is known of him thereafter.

Question: Who is Eudokia Of Trebizond's paternal grandfather?
Answer: Basil of Trebizond