Great Master 4

A Great Master is a character appearing fifth season episode "Kill the Boy". He is played by Davor Jozinovic.

Background
He is the head of one of the ancient slaving families of Meereen.

Season 5
After Ser Barristan Selmy is murdered by the Sons of the Harpy, Daenerys has the heads of the great families of Meereen arrested. She forces them into the catacombs were Viserion and Rhaegal are kept and then has the two dragons kill and devour one of the prisoners while the others watch in horror.

In the books
In the A Song of Ice and Fire novels, Daenerys never has the heads of the ancient slaving families of Meereen arrested after the attacks of the Sons of the Harpy. Instead she has these families deliver a child as hostage.